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Chapter 3: Planning and cancellation of the United States–Australia blockade operation
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Chapter 3: Planning and cancellation of the United States–Australia blockade operation
Imperial Headquarters’ conception of stage two operations
- Plans for stage two at the outbreak of war
Consequences of success in the early stages of the operation
Debate concerning attack on the Australian mainland
Research for the FS Operation
The postponement and reinstatement of the FS Operation
Preparations for the Fiji and Samoa Operation by Imperial Headquarters
- Strategic situation in the Fiji and Samoa area
Decision on the operational overview
Outline of the FS Operation
Central agreement between the army and navy
Various issues concerning the operation
Formation of the 17th Army
- Announcement of the order of battle
Announcement of the army orders
The departure of the 17th Army headquarters
Cancellation of the FS Operation
- Postponement of the FS Operation
Cancellation of the FS Operation
Leadership for subsequent operations
Notes
The war entered a new stage after the fall of Java and Rangoon in early March 1942. This was the transition from stage one to stage two operations. The campaign adopted for the opening of stage two was an advance into key strategic areas at the periphery of the region occupied during stage one. Representative of these operations were the advances into Midway and the Aleutian Islands, and the operation to blockade the United States and Australia.
The United States–Australia blockade operation (known as the "FS Operation", or simply the "F Operation") consisted of invading New Caledonia and Fiji, key locations in the South Pacific on the line of communication between the United States and Australia.
While the operation was scheduled to start on 18 May 1942, internal wrangling within Imperial Headquarters over the leadership of stage two operations caused numerous serious arguments. This wrangling characterises the antagonism that developed between the army and navy concerning the war more generally and operational leadership in the wider context of the Greater East Asian War. This is detailed in the History of Imperial Headquarters volume, but the issue as it relates to the FS Operation will be discussed in this chapter.
Imperial Headquarters’ conception of stage two operations
Plans for stage two at the outbreak of war
Did Imperial Headquarters hold plans for, or have any conception of, stage two operations at the time of the start of the war in December 1941?
The operation against the United States, Britain, and the Netherlands planned by the Army Department of Imperial Headquarters was called the Southern Operation. As the name implies, it was limited to the invasion of key strategic areas in the Southern Area. The extract in the planning documents relating to the objective of stage two operations stated the following: "The strongholds of the United States, Britain, and then the Netherlands in eastern Asia will be destroyed, and key strategic locations in the Southern Area will be occupied and secured."[1]
In contrast, the navy’s operational policy (within the navy, planning an operation was called "operational policy") against the United States, Britain, and the Netherlands clearly divided the operation into two stages: offensive campaigns in the Southern Area, and subsequent campaigns. An outline of operational leadership for both stages was clearly established, and contained the following:
Quickly attack and destroy enemy fleet and air strengths in the eastern Pacific. Occupy and secure key strategic locations in the southern region and establish a long-term and unassailable footing. In addition, attack and destroy the enemy fleet, ultimately crushing their fighting spirit.[2]
- 1. Occupy various regions, prepare to take key strategic sites, and secure maritime transport routes using a naval strength based on elements of the 3rd and 5th Fleets.
2. Make efforts to disrupt the enemy’s secure supply routes using elements of submarine and seaplane units.
3. Attack and destroy enemy forward bases using airbase units, a mobile carrier fleet, and units from item 1 above.
4. If it is possible to attack the main strength of the US fleet, then make efforts to destroy enemy strength with elements of the Combined Fleet, then muster the main strength to ambush and destroy them.
If it is possible to attack a significant British naval formation, then make efforts to seek out and destroy it after the US fleet has been silenced.
The fact that the Army Department of Imperial Headquarters had no plans whatsoever for stage two operations against the United States, Britain, and the Netherlands is principally put down to the traditional ideology of apportioning operational regions of responsibility to the army and navy (although this ideology was itself the target of much criticism). The main strategic concerns for the Army Department of Imperial Headquarters in the period after the invasion of key areas in the southern region were the continental fronts in China and Burma, and preparations against the Soviet Union. The main thrust of the operations in the southern region concerned breaking transport routes and air battles. Any decisive counter-attack from the Allies would come from air and sea strengths through the Pacific. This was to be carried out through a decisive naval battle, and was felt to be the sole domain of the navy.[4]
From these historical conditions, the conceptions of stage two campaigns adopted by Imperial Headquarters in planning at the beginning of the war were fundamentally policies adopting maintenance and protection, with the central point being a decisive battle against the main strength of the US fleet within the Japanese sphere of operations. A "Draft plan facilitating the end of war with the United States, Britain, the Netherlands, and Chiang Kai-shek" was formulated at the liaison conference on 15 November 1941. (Editor’s note: This was the actual leadership plan during the war.) The object of military conflict was modified in this plan as follows:[5]
Quickly execute military operations and destroy US, British, and Dutch bases in east Asia and the south-west Pacific. In addition to adopting a superior strategic position, secure the important natural resources and main transport routes and work towards establishing a position of long-term self sufficiency.
At an appropriate time after the completion of various stages of the campaign, lure the main strength of the US fleet into a destructive battle.
The sweeping naval victory at Hawaii at the opening of the war allowed contemplation that Japan was on the verge of an unprecedented victory. Subsequent army campaigns also continued to achieve unimagined successes.
Evaluation of the actual conditions within this mood was calm and reasonable, but it was extremely difficult to appropriately conduct operational leadership in subsequent battles.
Immediately after the victory at Hawaii, senior officers within the Army Department of Imperial Headquarters began investigating campaigns and operational leadership for offensive operations in key southern areas.
The Army Department’s strategy was to try and establish a long-term unassailable position from a base of largely predetermined occupied territories. The essential underlying policy was the completion of military preparations guarding against attack from the Soviet Union. The conclusion of the "Judgment of the situation in the northern region following the outbreak of war with the United States, Britain, and the Netherlands" was as follows:[6]
- The possibility of the Soviet Union positively mobilising against Japan at the outbreak of war is small. However, there is a strong chance of the United States strengthening military installations in the far east of the Soviet Union. It is essential that we are aware that the Soviet Union will adopt a variety of measures against us.
There is a potential for the outbreak of war between Japan and the Soviet Union depending on the development of the situation.
As early as 15 December 1941, the 2nd (Operations) Section and 3rd (War Mobilisation) Section of Imperial Headquarters and the head of the Military Affairs Section of the Army Ministry presented a memorandum of understanding, as follows: "Following on the completion of offensive operations in the southern area, military strength in the region will be reduced to approximately two hundred thousand (from approximately four hundred thousand at the start of the war)."
Army General Staff subsequently explained to the Army Ministry the plan that if the southern region operations could be completed by 24 February 1942, then an appropriate force from the south could be redeployed to the north (Manchuria).
In this way, the Army Department of Imperial Headquarters generally envisaged establishing a long-term unassailable position based in conducting a military build up against Soviet military action, and in adopting a defensive strategy in the southern region. But what had the Navy Department envisaged?
The navy had noted the smooth progress of various victories to this point, but was extremely anxious about initiating the second stage of the operation. The navy’s operational planning was divided into two broad categories.
The first concerned launching a direct attack against Australia and as much as possible foiling any counter-attack by blockading the supply route between Australia and the United States, all the while aiming to establish a long-term unassailable position. The second involved luring the main strength of the US fleet into destruction in a short-term decisive battle through attacks against places like Midway and Hawaii.
At that time, the idea of establishing a long-term position was favoured within the Navy General Staff. The Combined Fleet, however, was opposed to this view, and strongly pressed for a decisive short-term victory.
Neither the policies of a decisive short-term victory nor of protracted offensives were, however, made clear in stage two operational policies developed in the pre-war period.
The chief of staff of the Combined Fleet, Vice Admiral Ugaki, recorded the following in his diary dated 5 January 1942:[8]
- Stage one of operations must be generally completed by mid-March, in terms of overall offensive operations. As to where we should then spread our wings, whether to proceed to Australia, whether to set out against Hawaii, or whether to prepare a stand against the Soviet Union and take the opportunity to attack, needs to be planned for in mid-February. Research must be undertaken for the General Staff for this purpose.
Ugaki’s diary entry clearly indicates the mood of uncertainty prevalent at that time.
Debate concerning attack on the Australian mainland
Research for stage two operations was undertaken by the army and navy as a basis for their planning. Staff officers from the Army Department and Navy Department carried out concurrent research and discussions, including at the Imperial Headquarters–government liaison conferences. Research continued through late February and early March, further delaying the conclusion of the debate on whether to attack Australia.
Fundamentally, however, the army opposed the invasion of Australia and Hawaii on the grounds that they would extend national strengths beyond their limits. They did not oppose the United States–Australia blockade operation because of their faith in the absolute superiority of the Japanese navy’s capabilities.
The navy’s argument was that establishing a defensive posture was disadvantageous to the execution of long-term strategies. It was vital to adopt aggressive operational leadership whenever possible, thus forcing the enemy to take the defensive position.[9] Underlying this basic policy was support for the invasion of Australia, the main area from which the United States would launch counter-offensives against the Japanese. This was leadership of stage two operations through offensive strategies in the Pacific Ocean area, strategies that it was hoped would hasten the end of the war through naval surface battles in the region.[10]
The reasons for the army’s opposition to this policy were that the invasion of Australia was expected to require 12 army divisions, in addition to transport shipping requirements of approximately 1,500,000 tonnes. Reflecting on the bitter experience of the China Incident, the chances were high that an invasion would extend over the whole of the Australian continent.
In order to supply these troops, the size of the Japanese build up against the Soviet Union in Manchuria and the strength of the main China front would need to be substantially reduced. This was, however, considered extremely disadvantageous to the stability of the overall long-term position.
Of more importance was the problem of shipping. The total amount of shipping conscripted by the army at the beginning of the war amounted to 2,100,000 tonnes. However, it was planned that following the operations in the southern region, these ships would be gradually discharged after five months had elapsed from the outbreak of war (around April 1942) until the total tonnage was around 1,000,000 tonnes by July 1942. In normal times, Japan maintained around 3,000,000 tonnes of civilian commercial shipping. Virtually this entire amount was initially mobilised for the war effort. This plan facilitated a long-term war of a scale commensurate with the national strength outlined in the materials mobilisation plan of fiscal 1941.
This way of thinking was a fundamental prerequisite for war leadership. If the required levels of shipping were allowed to deteriorate, then it was clear that this would directly damage national material strength. Even if the army could supply the required strength for the proposal to invade Australia, there were grave fears that the problem of supplying shipping would destroy the fundamental basis for executing the war.[11]
The pressing issue of strengthening policies was discussed at the Imperial Headquarters–government liaison conference on 10 January 1942. It was decided to blockade the supply from Britain and the United States in India, and to deny British cooperation. With regards to Australia (including New Zealand), the following was determined:
- Proceed with the southern operations, all the while blockading supply from Britain and the United States and strengthening the pressure on Australia, ultimately with the aim to force Australia to be freed from the shackles of Britain and the United States.
Consequently, the proposal was made on 15 January that the Army Department mainly be responsible for India, and the Navy Department be responsible for Australia.[12] The designs of the navy concerning Australia increasingly came to be supported in this way.
Central to this problem was the "Outline of future war leadership". Discussions within the army and navy offices of Imperial Headquarters continued from mid-February, but confusion compounded without any conclusions being reached.
To alleviate this confusion, a conference between heads of the various army and navy sections (comprising the heads of both the army and navy Military Administration Bureau and Operations Department) was held on 4 March. The initial position argued by the navy was as follows:
- 1. We are currently engaged in pursuit operations in the Pacific as a result of the overwhelming victory at Hawaii.
2. The enemy will be able to take a breather and regroup if we do not take this opportunity to completely smash their naval strength.
3. Further, the enemy’s base for counter-offensives must be ruined, preventing them from mobilising a counter-attack at any time or place.
4. This is a heaven-sent opportunity to attack the United States individually (distinct from Britain, the Netherlands, etc.).
5. The offensive must be undertaken to fulfil the strategic requirements outlined above. We are determined not to allow the establishment of a defensive posture at this time.
- 1. It is not valid to claim that future operations in the Pacific will be "pursuit operations". With no pursuit at the actual site of battle at this time, it must be considered [a phase of] a "strategic pursuit". To seek the enemy main strengths in Australia or Hawaii must be said to be exceedingly dangerous. We cannot dispel misgivings over this expression "pursuit operations".
2. We would like to pay close attention to the extent of this offensive. An operation that exceeds the limits of both military and national strength can have no other fate than failure.
3. When an enemy is forced into a defensive position, it is natural for us to take hold of the offensive in order to suppress initiation of the inevitable counter-offensive. However, such an offensive must be a tactical offensive. This strategic operation is not a measure that we must take at this time.
4. Dominion over the western Pacific, in order to establish an unassailable position in Greater East Asia, must first have the contribution of a strategic position (including tactical offensives) in the Pacific Ocean.
The discussion continued for three hours, after which time the navy did not express a desire to invade the distant areas of Hawaii and Australia, but argued the necessity of destroying the enemy’s bases of operations and preventing the initiation of the enemy counter-attack at an appropriate time and place.
As a result, agreement was reached concerning the essence of the "Outline of essential future war leadership", as follows:
- 1. In order for Britain to yield and to force the United States to lose its will to fight, discussions on concrete measures will be undertaken at an appropriate time, while continuing preparations to establish a long-term unassailable position through extending heretofore military victories.
2. Territories and key transport routes will be secured, the exploitation of vital national raw materials will proceed, and efforts will be made to reach a position of self-sufficiency and to increase national military strength.
3. More positive tangible means of war leadership will be established taking into consideration our national strength, the promotion of strategy, the military situation between Germany and the Soviet Union, relations between the United States and the Soviet Union, the situation in Chungking, and other factors.
Up to that point, the navy had strongly emphasised the removal of "continuing preparations to establish a long-term unassailable position" in the first clause introduced above.
This overview of war leadership was adopted without alteration at the Imperial Headquarters–government liaison conference three days later. Detailed investigation of the issues surrounding the "Outline of essential future war leadership", which seems to have been moderated by army and navy disagreements, is undertaken in the History of Imperial Headquarters and History of war leadership volumes of this series. The establishment of the outline effectively ended debate concerning the invasion of Australia.
Research for the FS Operation
The army also keenly felt the need for measures to bring about the end of the war. To this end, there was approval for limited offensive operations to establish an unassailable position providing they did not impede the progress of military preparations against the Soviet Union or damage operations in China.[13]
The army chief of staff, Sugiyama Gen, submitted the following response to the emperor on 6 January 1942:
Having achieved the completion of stage one of the campaign, operations to blockade the United States and Australia, as well as operations in the Indian Ocean, are being undertaken primarily by the navy. Investigations by subordinates are continuing in accordance with previously submitted draft proposals to promote the end of the war.[14]
On 24 January, staff officer Prince Takeda presented chief of operations Tanaka with a report outlining the results of research, as follows:
- 1. The navy will use second string air strengths from Rabaul for the invasion of Samoa and Fiji. Because base strengths are not sufficient, a large garrison will not be established after the operation to secure the area. It is expected that four aircraft carriers will be used in the operation.
2. (Abbreviated by editor: relates to Indian Ocean)
3. Concerning the relationship between the Samoa and southern operations, the former must be executed at a time after the southern operations have been completed.
On 26 January, the army made the following announcement during a meeting between the offices of the army and navy responsible for operations:[15]
- 1. It is essential to monitor the relationship between the Fiji–Samoa Operation and the north, given the necessity of considering a possible deployment to the north if military actions occur.
2. We would like to see a slight strengthening of operations to break trade in the Indian Ocean.
- 1. It is our consideration that the Fiji–Samoa–New Caledonia Operation should be carried out as the next navy operation.
2. A defensive position will initially be adopted in the north in the case of military actions.
3. The FS Operation will be carried out after the operation to break trade in the Indian Ocean is scaled back.
On 30 January the head of the 2nd (Operations) Section of the Army Department, Colonel Hattori Takushirô, explained the operation proposals discussed up to that time with the navy to the army minister, Tôjô Hideki.
The army minister indicated his assent concerning the FS Operation, as follows:
- There is no consensus on the Australia operation even between high command and the ministers. Agreement has been reached concerning the plans to invade Fiji and Samoa. I think there is reason for caution concerning the method of execution of the New Caledonia invasion, though I cannot say there is no agreement.
Although there was never a formal decision concerning the FS Operation, the army nevertheless continued with concrete preparations, and on the following day sought approval for invasion operations against eastern New Guinea and the Solomon Islands.
Army Department’s chief of operations, Tanaka, who had championed operations on the southern front, submitted his opinions in a telegraph on 10 February. The telegraph outlined the planned units to be used in the FS Operation, and indicated that the shipping for the operation was to be that returning from the Java operation. Further, the operation was to be initiated from as early as late March through to early April.[16]
Army chief of staff Sugiyama expressed his convictions to his navy counterpart, Nagano, on 16 February as follows:[17]
- Discussions have previously been conducted concerning leadership in operations after the completion of stage one in the southern region. We have now achieved our goal of favourably advancing the operation, even in Java. It is now essential that subsequent strategies be formulated as soon as possible, and that decisions are taken on research on various related issues at the upcoming liaison conference.
An essential part of this research concerns strategies against Australia. Great deliberation must be given to this consideration. It is thought that Australia will be the main base for mounting the US and British counter-attack against Japan, so strategies to crush this counter-offensive are essential. However, these strategies, which will not aim to deal with the entire continent, will probably develop from operations in one part of Australia into a war of attrition spread over many areas. There are grave fears that the operation will gradually expand uncontrollably and slide into a total multi-front war. Consequently, because measures to control all of Australia should not be adopted, it is felt necessary to refrain from invasion operations in any part of Australia.
However, it is essential to blockade the transport of troops and matériel to Australia in order to smash the enemy counter-offensive. To this end, the operations to occupy Fiji, Samoa, and New Caledonia in the Pacific are felt to be of great importance.
As is clear from the trends in research undertaken by those responsible for the development of these strategies, I would especially like consideration of these matters.
It can be said that this statement by the army to the navy is a formal declaration of the army’s position: "We do not support operations against Australia; however, the execution of blockade operations between the United States and Australia is acceptable."
The postponement and reinstatement of the FS Operation
Preparations for the FS Operation were under way after an internal decision was taken by the Navy Department of Imperial Headquarters for its execution in April. The decision was then taken, however, to postpone the operation owing to the overall development of the war situation.
The Army Department of Imperial Headquarters decided on an overview for stage two operations in mid-March according to the "Outline of essential future war leadership" established on 7 March, as follows:[18]
- 1. The occupation of key areas must be completed and a defensive position adopted as soon as possible. In addition, military government must be established to secure order and the long-term unassailable position.
2. Key areas of central Burma will be occupied. Plans will be formulated to destroy the enemy army, particularly the Chungking Army currently in Burma.
3. The strategic dominance we have obtained in the opening stages of the war must be expanded to prepare for the long-term unassailable position. In addition, we must steadily force the United States and Britain into adopting a passive defensive position, and in order to bring about the end of the war, preparations must be made to undertake operations in key strategic locations outside of previously occupied areas.
4. In addition to strengthening the effectiveness of national defences, troops despatched at an appropriate time to the south must be prepared, similar to the adjustment of previous operations, and military preparedness in key areas strengthened.
5. Efforts must be made to quickly resolve the China Incident through the combined application of military and political strategies and, where circumstances permit, by using the results of the southern campaigns.
6. The outbreak of new incidents with the Soviet Union must be avoided. In addition, military preparedness guarding against a change in circumstances relating to the Soviet Union must be strengthened.
- Fiji, Samoa, and New Caledonia are not just important locations on the line of communication between the United States and Australia; they are also key localities for the enemy’s counter-attack from the south-east direction. Consequently, invading these areas will be highly advantageous from both a political and military perspective, by establishing a strong strategic position in the southern area and increasingly isolating Australia.
As an extension to current operational planning in the southern area, a force based on nine infantry battalions, directly controlled by Imperial Headquarters, should undertake the invasion at an opportune time no earlier than June. The navy has also undertaken similar research in cooperation with the army.
The FS Operation was scheduled for "an opportune time no earlier than June" because the fourth phase of the navy’s stage one operations in the Indian Ocean was to finish in early April, and because the army’s Port Moresby operation was slated for May.
However, a US navy task force raided Marcus Island on 4 April. The Japanese Combined Fleet was at that time undertaking redeployment of the formation of its two aircraft carriers for the Indian Ocean operations. As a result of the attack, the schedule for the Indian Ocean operation was extended by ten days.
On the other hand, the army too had decided to temporarily deploy the Kawaguchi Detachment and the 41st Infantry Regiment, which were planned for assignment to the FS Operation, to subjugation operations in central-south Philippines. This sequence of measures naturally delayed the timing of the FS Operation.
After that, on 5 April, the Navy Department of Imperial Headquarters made an internal decision to undertake the Midway invasion operation, which was based on submissions by the Combined Fleet.[19] The date of the operation was set at early June. The FS Operation was fated yet again to be delayed.
The Navy Department, on that day, delivered to the army an unofficial memorandum containing the contents of the decision. The main points of this were as follows:
- 1. Strengthen the 4th Fleet and invade Port Moresby by 10 May.
2. Invade Midway, and Kiska in the Aleutian Islands, in early June, and at the same time raid Dutch Harbour and Attu. Seek an opportunity to destroy the main strength of the enemy fleet during this time.
3. Invade Fiji, Samoa, and New Caledonia in early July.
Further, it is hoped that the Midway invasion will be a joint operation between the army and navy, given the precedent of the planned Kiska invasion. If this is not possible, the navy will execute the invasion independently.
The operational policies signifying the start of stage two operations, as contained in this internal memorandum, were officially discussed between the operations offices of the army and navy on 12 April.
The army had previously admitted the necessity of the operations in the Aleutian Islands, and so readily agreed in principle with the invasion, but temporarily held the deployment of its units in reserve. The army strongly opposed the Midway invasion, however, but was unable to veto it because the navy had indicated that it could execute the operation independently.
It was decided to overview the deployment of army units based on previous research through mutual consent of the army and navy, and that the operation would be undertaken in early July. Meanwhile, the invasion of the Bataan Peninsula in the Philippines had ended and the fortress at Corregidor came to be regarded as a problem. The Southern Area Army swept away all opposition during its pursuit operations in northern Burma. The Anglo–Indian conference, which aimed to strengthen the union between the two, was held on 10 April, but the political situation between Britain and India was in turmoil.
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Preparations for the Fiji and Samoa Operation by Imperial Headquarters
Strategic situation in the Fiji and Samoa area
On 19 March 1942, the army chief of staff Sugiyama presented the emperor with an overview of outlying strategic areas. According to a note in the margin of the original response to a question from the emperor, the military situation in the Fiji and Samoa area was as follows:[20]
- Fijian islands (Viti Levu) (British)
- New Zealand troops: 7,000–8,000
Local volunteer troops: 3,000
Approximately 50 aircraft
- US Marines: 750
Aircraft: 1 (?) squadron
- Troops: approximately 3,000 (said to be an American–Australian garrison, but not confirmed)
Aircraft: approximately 60
According to postwar investigations, the Allies paid great attention to the line of supply between the United States and Australia from an early time. The brigade of New Zealand troops which had been sent to Fiji in November 1940 was further strengthened to total approximately four thousand troops by December 1941.
The Allies in the pre-war period had underestimated the offensive strength of the Japanese armed forces. As a reaction against this, even experts tended to overstate the speed of the Japanese thrust once the war had started. For example, a prominent US authority issued the following warning concerning New Zealand on 8 January 1942: "There is a possibility that a Japanese force comprising one division and four aircraft carriers will invade Fiji after 10 January." The British chief of staff concluded at the end of March that: "The Japanese advance will be limited to the line of New Caledonia, Fiji, and Samoa, and while it would be extremely difficult, is not impossible that they would continue to New Zealand."
The main strength of a US reinforcement detachment headed for New Caledonia at the beginning of 1942. This force included an infantry brigade, an artillery regiment, a light tank battalion, an anti-aircraft regiment, and a pursuit battalion under the command of a major general. Only a pursuit battalion was stationed on Fiji.[21]
The situation adjusted to the beginning of April 1942 was as follows:
- Fijian islands
- New Zealand army: 8,000
US army land personnel: 10
US army aircrew: 700
(Pursuit planes: 25)
- US army marines: approximately 500
- US army land personnel: 16,000
US army aircrew: 2,000
(Pursuit planes: 40)
Australian army: 330
Decision on the operational overview</a>]
Research preparations for the FS Operation were undertaken prior to the battle of the Coral Sea with the assumption that Port Moresby would be in Japanese hands. The first problem to be the subject of research for the operation was the order of invasion of the three key areas of Fiji, Samoa, and New Caledonia. Naturally, three proposals were considered:
- Proposal 1: First invade New Caledonia, then invade Fiji and Samoa at roughly the same time.
Proposal 2: First invade Fiji and Samoa at roughly the same time, then invade New Caledonia.
Proposal 3: Invade Fiji, Samoa, and New Caledonia at roughly the same time.
After consideration of the advantages and disadvantages of the three proposals, the first was adopted.
The next issue was whether the extremely distant island of Samoa should be secured after the initial invasion. It would certainly be beneficial for a thorough blockade of the supply route between the United States and Australia for all three locations to be heavily secured. Samoa would have high value as an advance base for Fiji; furthermore, its naval strategic value would increase after the invasion. However, there were doubts as to whether the island could be secured. The Combined Fleet in particular expressed the seriousness of this doubt. The army initially argued for army garrisons to be stationed on Fiji and New Caledonia, and for a navy garrison at Samoa. The navy, however, argued for the withdrawal of troops after key installations on Samoa had been destroyed. As a result of discussion, it was decided that an army garrison would initially be established on Samoa, and a final decision whether to secure the island or to destroy installations and withdraw would be made dependent on the conditions after the invasion.
The site of the invasion operations was 7,000–8,000 kilometres distant from the Japanese mainland. It was natural, therefore, that great concerns were held for the maintenance of supply after the invasion. The navy had initial responsibility for supplying army units and evacuating casualties, for example, so it was recognised that no disruption to the supply line would occur as long as the Japanese navy maintained its dominance in the region.
The army strength for the operation comprised nine infantry battalions, as detailed below, and an army strength command group (17th Army):
- South Seas Force (based on the 144th Infantry Regiment from the 55th Division)
41st Infantry Regiment from the 5th Division
35th Brigade Headquarters and 124th Infantry Regiment from the 18th Division
One tank company
One mountain artillery regiment
One heavy artillery company
Two anti-aircraft battalions
One independent engineer regiment
Other related army units
Among these, the unit from the 18th Division led by Major General Kawaguchi Kiyotake had, at the beginning of the war, invaded British Borneo and the 41st Division had participated in the Malaya campaign. These units were considered expert troops, and, along with the South Seas Force, had experience since the start of the war in sea crossings and landings in the face of the enemy.
Army strength for the operation was divided between key targets (with Fiji as the main target) as follows:
- Fiji: Main strength of army, based on five infantry battalions (Kawaguchi Detachment plus two battalions from 41st Infantry Regiment)
New Caledonia: Based on two infantry battalions (South Seas Force)
Samoa: Based on one infantry battalion (41st Infantry Regiment, two battalions missing, and one special naval landing force battalion)
The naval strength for the operation, in addition to the landing force troops mentioned above, included the following units:
- 2nd Fleet (based on two warships, ten heavy cruisers, two light cruisers, and 32 destroyers)
4th Fleet (based on four heavy cruisers, three light cruisers, eight destroyers, and four submarines)
1st Air Fleet (based on six aircraft carriers)
- 7 May: invade Port Moresby, South Seas Force to assemble at Rabaul by mid-June after invasion to prepare for invasion of New Caledonia
7 June: invade Midway
18 June: Midway operation units to assemble at Truk and prepare for FS Operation
1 July: mobile carrier fleet (based on six aircraft carriers) to sortie from Truk
8 July: invade New Caledonia
18 July: invade Fiji
21 July: invade Samoa
The South Seas Force sea-route invasion of Port Moresby returned in failure owing to the battle of the Coral Sea, which occurred in early March. As a result, Imperial Headquarters decided to incorporate a second invasion of Port Moresby as part of the FS Operation. The Army Department of Imperial Headquarters, however, determined that the double deployment of the South Seas Force was untenable, so consequently assigned a detachment based on the 4th Infantry Regiment from the 2nd Division (called the Aoba Detachment) as the force to participate in the operation. The Aoba Detachment also had experience from the invasion of Java.
Outline of the FS Operation
Following this course of events, Imperial Headquarters decided on an operational plan on 18 May. The main points of this plan are as follows:[23]
- No. 1 Operational objective
- 1. The objective of operations by the 17th Army is to invade key locations in the New Caledonia, Fijian islands, and Samoan islands areas. In addition to strengthening the blockade of the communication route between the United States and Australia, Port Moresby will be invaded, thus bringing the Coral Sea under control and smashing enemy plans for a counter-offensive in that region.
- 2. The army will cooperate with the navy to seek an opportunity to make a surprise landing with one detachment in southern New Caledonia and invade that key area. Following this, the main force shall strike and land at Viti Levu, with elements simultaneously landing on Tutuila. The islands and surrounding areas will then be brought under control.
At an opportune time during this period, a force will be landed near Port Moresby to invade and secure the town and surrounding areas.
- 3. The army will begin the operation at an appropriate time around the beginning of July according to the situation with naval operations.
4. The army will act in concert with the navy’s mobile carrier force operations in the waters to the east of the Australian mainland and in the area around the landing site. The following landing operation will be conducted under the protection of naval forces.
First, a surprise attack and landing at the south of New Caledonia, Noumea, and other areas will be undertaken by a detachment that will have assembled at Rabaul in late June.
Next, a force that will have assembled at Parao in mid-June will land near Port Moresby and invade the surrounding area.
The final force, after assembling at Truk in early July, will attack and land an appropriate force on Viti Levu, with elements to mount a surprise landing on Tutuila, Suva, Pago Pago and other key areas.
5. The New Caledonia, Fiji, and Samoa offensive units will occupy the key areas of Noumea, Suva, and Pago Pago, and then conduct mopping-up operations on the islands. At an appropriate time, in cooperation with the navy, the surrounding islands will be subjugated.
The Port Moresby offensive unit will secure Port Moresby in cooperation with the navy, and then subjugate the surrounding area.
6. After the invasion, key areas in New Caledonia and Fiji will be secured.
Up until immediately after the invasion on Samoa, Imperial Headquarters will issue instructions either to destroy certain installations in specified areas and then withdraw, or to secure them indefinitely.
The army will hand over the garrison at Port Moresby to the navy and withdraw, as far as the conditions of the navy permits.
- 7. The deployment and responsibilities of army units is as follows:
The South Seas Force (based on three infantry battalions) will land in southern New Caledonia, and after attacking key strategic sites in Noumea, will subjugate the entire island and secure key sites, especially areas of natural resources.
The Aoba Detachment (based on three infantry battalions) will land near Port Moresby, then attack and secure key strategic areas.
The army main strength (based on approximately five infantry battalions) will land on Viti Levu island, then after attacking key strategic sites, will conduct mopping-up operations throughout the island and subjugate the surrounding islands. Key locations in Fiji will be secured.
The Higashi Detachment (based on one infantry battalion) will land on Tutuila with a special naval landing force (less one battalion), then attack military installations at Pago Pago before subjugating the surrounding islands.
- 8. The army will assemble the South Seas Force in Rabaul in late June. The Aoba Detachment and remaining units will first assemble in Davao in mid-June, and then the Aoba Detachment will assemble in Truk, by way of Parao, in late July.
9. The South Seas Force will sortie from Rabaul under naval escort at an appropriate time following on the commencement of operations by the naval mobile carrier force assembled in Truk. The South Seas Force will take advantage of the naval operation near New Caledonia and attack and land at Noumea, and then attack key locations, particularly airfields.
10. The Aoba Detachment will leave from Parao under the protection of the 4th Fleet to land and attack Port Moresby at an appropriate time between the start of the New Caledonia operation and the start of the Fiji and Samoa operations.
11. The army main strength and the Higashi Detachment will seek an opportunity to leave Truk at an appropriate time under naval escort. Surprise landings will be undertaken virtually simultaneously on Viti Levu island, following from the operations of the mobile carrier force in the Fiji and Samoa areas. Key locations, particularly military installations and airfields at Suva and Pago Pago, will be attacked.
12. Thereafter, the operations of all units will be as follows:
The South Seas Force, in addition to securing key areas around Noumea, will then subjugate the entire island, particularly securing areas of natural resources.
The Aoba Detachment, in addition to securing Port Moresby in concert with the navy, will then subjugate key neighbouring areas.
The army main strength, in addition to securing Suva and other key areas, will undertake mopping-up operations within Viti Levu island, and will then subjugate nearby islands at an appropriate time with the cooperation of the navy.
The Higashi Detachment, in addition to attacking military installations, will undertake mopping-up operations within Tutuila island, then will subjugate nearby islands at an appropriate time with the cooperation of the navy.
13. The army will move to a defensive stance after the invasion of each key strategic area and, in cooperation with the navy, will secure key locations within the occupied area. However, the garrison in the Port Moresby area, in line with naval reserve strengths, will be handed over to the navy at an appropriate time, after which the army force will withdraw. Furthermore, in the case of a withdrawal from Samoa, all military installations will be thoroughly destroyed prior to withdrawal at a time one month after the end of the invasion operation.
The Navy Department of Imperial Headquarters issued an outline of operational policy in response to this, as follows:
- No. 1 Operations against New Caledonia, Fijian islands, and Samoan Islands areas
- 1. A force based on the 2nd Fleet and 1st Air Fleet under the command of the 2nd Fleet will enter Truk in mid-June and begin preparations for the operation after the completion of the offensive operations against Midway.
2. A mobile carrier force, based on the 1st Air Fleet, will sortie from Truk at the beginning of July and assist the New Caledonia invasion force in the vicinity of Noumea. After that, it will undertake appropriate manoeuvres in the waters to the east of Australia before proceeding to the Fiji and Samoa area on around 20 July. In addition to destroying enemy sea and air strengths in the area, the force will assist the invasion operations in each location.
3. The various escort units, in association with the aforementioned movements of the mobile carrier force, will protect army forces and, after departing from appropriate staging points, will undertake landings in the face of the enemy at New Caledonia, then at Viti Levu and Tutuila.
4. The naval landing force to be used in this operation will be a one battalion strength special naval landing force, planned to primarily be used in the invasion of Tutuila.
5. The decision whether to secure or abandon Samoa immediately after the invasion stems from a deficiency in air strength. A decision will be made immediately after the Tutuila invasion, after discussions concerning the result of the Midway operation, and from estimations after the New Caledonia invasion.
- 1. The 4th Fleet, the unit assigned for the operation, will proceed to the waters east of Australia to wait an appropriate opportunity to escort the army force to undertake a landing in the vicinity of Port Moresby.
2. The landing will be undertaken by a battalion of special naval landing troops in concert with the army troops.
As seen above, the various operational outlines of the army and navy were concurrently formulated. Discussions also continued concerning a central agreement between the army and navy in order to execute the operation. It was completed and adopted on 15 May and divided into two parts: agreement on the operations in the New Caledonia, Fijian islands, and Samoan islands areas; and agreement on the Port Moresby operation.[24] The complete text of the agreement is given below:
Central agreement between the army and navy relating to operations in New Caledonia, Fijian islands, and Samoan islands areas
No. 1 Operational objective
- Invade key locations in the area of New Caledonia and the islands of Fiji and Samoa. In addition to strengthening the blockade between the United States and Australia, the operation will smash enemy plans to counter-attack from that region.
- 1. The invasion of key locations in the area of New Caledonia and the islands of Fiji and Samoa will be executed by the army and navy in cooperation.
2. Maintain mastery over the enemy fleet and air strength. First, undertake a surprise attack at New Caledonia. Then undertake surprise landings on the islands of Fiji and Samoa by invading key locations such as Noumea, Suva, and Pago Pago.
3. Mopping-up operations will be conducted within the islands after such key locations as Noumea, Suva, and Pago Pago have been invaded, then the surrounding islands will be subjugated at an appropriate juncture.
4. The army and navy will cooperate to secure key locations after the invasion of New Caledonia and Fiji. The navy will then proceed with the establishment of an operational base. After the invasion of key areas of Samoa, either destroy various military installations and withdraw, or secure the area.
- Army
Command: 17th Army headquarters
Strength: main force of 17th Army (three battalions each from the 5th Division, 18th Division, and 55th Division)
Navy
Command: 2nd Fleet headquarters
Strength: force based on 1st Air Fleet of the 2nd Fleet
- 1. The main strength of naval units will assemble at Truk in mid-June.
2. After the majority strength of army units have assembled at Davao in mid-June, then proceed to the staging point by way of Parao.
3. Elements of the army units will assemble and stand to at Rabaul and undertake preparations for the operation.
- New Caledonia offensive units will assemble at Rabaul in late June.
Fiji and Samoa offensive units will assemble at Truk in early July.
- At an appropriate time in early July according to the situation of the Combined Fleet operations.
- 1. The navy is responsible for undertaking operations with a strong mobile carrier force to smash enemy sea and air strengths in the waters to the east of Australia and around the landing point, in addition to air elements assisting the landing.
2. The New Caledonia offensive units (based on three infantry battalions) will leave the assembly point after the start of operations by the mobile carrier force, then proceed under naval protection to undertake a surprise landing in the southern part of New Caledonia. Noumea will be invaded first, followed by other key locations.
3. The Fiji offensive units (based on five infantry battalions) and the Samoa offensive units (based on one infantry battalion and one naval landing battalion) will leave the staging point at an appropriate time and proceed under naval protection to undertake simultaneous surprise attacks at Viti Levu and Tutuila. Invade Suva and Pago Pago followed by other key locations.
4. Mopping-up operations will be conducted within the islands after such key locations as Noumea, Suva, and Pago Pago have been invaded, then the surrounding islands will be subjugated by the army and navy in concert at an appropriate juncture.
5. Priority will be given to establishing defences at key locations with the cooperation of the army and navy after the invasion of key areas. The navy will proceed with the establishment of an operational base and strive to fulfil the objectives of the operations.
6. A decision will be made by central authorities up to immediately after the invasion whether to destroy military installations and withdraw from the Samoan Islands, or whether to secure the area for the long term.
In the case of withdrawal, various military installations will be completely destroyed at a time approximately one month after the operation.
The outline of the withdrawal operation will be conducted according to the central agreement and agreements with the local army and navy commanders.
- The army and navy will cooperate.
However, in the case where the army and navy, including naval landing troops, participate in concurrent operations in the same area, command will be unified in the position of the most senior officer.
- 1. Garrison duties on New Caledonia and Fiji will mainly be the responsibility of the army. Patrolling of the sea and sky in the area will be the responsibility of the navy.
2. The army will be responsible for the garrison on Samoa in the case it is to be secured. The navy will be responsible for securing the logistics line of communication. Responsibility for anti-aircraft patrolling of the sea and sky in the area will be with the navy, as far as conditions permit.
3. Appropriate agreements concerning garrisons on land will be reached between army and navy commanders in an area where troops from both services are stationed.
- 1. Communications will be according to the "Army and navy central agreement relating to communications for the AL, MI, and F Operations".
2. The navy will provide aircraft, whenever possible, in order to coordinate command with the army when required.
- The navy will assist in supplying the army and evacuating casualties as required.
- Agreements between commanders of the army and navy will be formulated as follows:
Agreements between the commanders of the 17th Army and the 2nd Fleet will be made at Truk on around 20 June.
Agreements between the commanders of army detachments and naval escort units will be made immediately prior to each operation at the respective staging points.
- Exclusive military location maps
Topographical maps
New Caledonia, 1:300,000 scale
Viti Levu, 1:300,000 scale
Hydrographical maps
No. 2212, No. 2336, No. 2401, and No. 2402
- Central Standard Time
- New Caledonia operation: No. 2 (also NK) Operation
Fiji operation: Fu (also FI) Operation
Samoa operation: Sa (Also SA) Operation
All above known combined as F Operation
No. 1 Operational objective
- Invade Port Moresby, destroy enemy offensive positions in eastern New Guinea, and bring the Coral Sea under control.
- At an appropriate opportunity during the operations against New Caledonia, Fiji, and Samoa, the army and navy will cooperate to land near Port Moresby and invade and secure the surrounding area.
- Army
Command: 17th Army Headquarters
Strength: elements of the 17th Army (Aoba Detachment based on three battalions from the 2nd Division)
Navy
Command: 4th Fleet Headquarters
Strength: force based on 4th Fleet (including approximately one battalion strength naval landing party)
Note: elements of the 11th Air Fleet will participate in this operation.
- 1. Army units will assemble in Davao by mid-June, then proceed to the operation staging point.
2. The navy will use an appropriate force (including units not assigned to the actual operation) to protect the transport of the army units to the staging point.
- The staging point and time have been determined for Davao in mid-June.
- The operation will begin at an appropriate time after the start of the New Caledonia operation and prior to the start of the Fiji and Samoa operations.
- Determined in discussions between the commanders of the army and navy.
- The army and navy will cooperate.
However, in the case where the army and navy, including naval landing troops, participate in concurrent operations in the same area, command will be unified in the position of the most senior officer.
- 1. Guarding of key landing sites in the vicinity of Port Moresby will initially be undertaken through cooperation between the army and navy. If there is a surplus of navy troops available after the completion of the New Caledonia, Fiji, and Samoa operations, then the army will hand over the garrison to the navy and withdraw at an appropriate time.
2. The navy will be responsible for patrolling the seas and sky in the Port Moresby area.
- Communications will be according to the "Army and navy central agreement relating to communications for the AL, MI, and F Operations".
- The navy will assist in supplying the army and evacuating casualties as required.
- Agreements between commanders of the army and navy will be formulated as follows:
Agreements between the commanders of the 17th Army and the 4th Fleet will be made at Truk on around 20 June.
Agreements between the commanders of army detachments and naval escort units will be made at Parao on around 27 June.
- Exclusive military location map
Hydrographical maps
No. 815 and No. 816
- Central Standard Time
- Port Moresby operation: Mo (also MO) Operation
Various issues concerning the operation
Some issues of particular interest concerning the FS Operation emerged at Imperial Headquarters.
The first was the issue of responsibility for military administration of the occupied territories. Since the start of the war, the army and navy had jointly determined responsibility for the administration of each particular invaded territory.
The responsibility for the military administration of occupied territories in the South Pacific Area was with the navy. It had been planned that the army’s South Seas Force would be transferred to the South-West Area after the completion of the invasion of Rabaul. Consequently, that the navy was to be responsibility for this area was not at issue. However, a problem developed between the army and navy over the issue of responsibility for military administration during the FS Operation.
This concerned the operation of units, guarding, placement and other key factors in the region of the operation (area of occupation). The army felt that it was natural for them to have main responsibility for military administration of operational areas because army units were primarily deployed in the land operations.
Nickel deposits on New Caledonia further complicated the argument over military administration. The issue was not resolved, despite the responsibility for its administration being apportioned in the order of battle for the operation, which was issued on 18 May.
The Operations Section of the Army Department in Imperial Headquarters would not yield and stressed that the army should take charge. The reason for their position was:
- The main strategic reason for the New Caledonia operation is not to secure natural resources, but to effect a blockade between the United States and Australia. We will not be swayed into accepting that the primary strategic reason for the operation is to secure natural resources.
It is not appropriate to decide matters of agreement between the army and navy because of contingency over military administration. (Editor’s note: Spoken in opposition to the above statements made in Army General Staff.) The Navy General Staff is not disposed to the navy taking charge of military administration in the future. Navy units being concerned with issues like military administration may distract them from their primary focus on strategic mobility. It is natural that the army take charge of military administration in New Caledonia within the limits of maintaining peace and regional self-sufficiency. However, it is also natural that securing natural resources must be incorporated in the materials mobilisation plan. Further, it is desirable that natural resources in the region be developed with the cooperation of the navy and army. There will, by necessity, be navy bases within the sphere of the army’s military administration. I would like to see every effort given by the army to accommodate these bases.[25]
Lieutenant General Tanaka agreed with this proposal, and subsequently those responsible for army and navy military administration bureaus agreed, on 28 May, that the army had responsibility for military administration and that the development of natural resources would be managed with the cooperation of the army and navy.
By this process, the 17th Army command issued the "Overview of control in occupied territories following on from the F Operation" on 3 June. It also determined that the base yield for the first year of developing essential natural resources would be 2,000 tonnes of nickel, and as much cobalt as could be mined. As New Caledonia was French territory, and as Imperial Headquarters wished to remain on friendly terms with the Vichy French, it took the position that formal military control would not be administered on the island.
A further issue concerned strategies against the Australian government. While the Navy Department within Imperial Headquarters championed the debate over the invasion of Australia, the army opposed the plan for a range of reasons.
On 25 May, chief of operations Tanaka made inquiries concerning this issue to assistant chief of staff Tanabe. They recognised the need to integrate a strategy against Australia during the execution of the FS Operation. Psychological warfare was considered especially important.
The prime minister, Tôjô, in response to the situation after the fall of Singapore, made an address in the Imperial Japanese Diet on 17 February, calling on the leaders and people of India, Australia, and the Netherlands East Indies to end their futile resistance. He again called on the leaders of Australia in an administrative policy speech during an extraordinary session of the Diet on 28 May, indicating that there would be no other opportunity but the present to act decisively.
Assistant chief of staff Tanabe and chief of operations Tanaka, following the spirit of the address by the prime minister, pursued a strategy to accurately illustrate Japan’s true intention to Australia’s leaders, namely to respect the sovereignty of Australia’s territories in return for Australia promising to maintain neutrality. The ultimate aim was to incorporate Australia politically into the fold of the Greater East Asian Co-prosperity Sphere, but in the short term the strategy was to remove Australia from the war.
Chief of operations Tanaka investigated the feasibility of several methods, including the despatch of junior special emissaries, and political manoeuvring by using the Australian government representative in New Caledonia and the undersea telegraph cable that ran between Sydney and Noumea.
Tanaka considered that, in the case where Australia would not respond to these demands, it would be necessary to undertake psychological warfare in the form of attacks on Australia. In addition, he would plan to disrupt contact between the Australian government and the governments of other countries. High command of the army had also long waited for the arrival of a good chance to solve the Australia problem, an opportunity that was presented with the execution of the FS Operation.
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Formation of the 17th Army
Announcement of the order of battle
The order of battle for the 17th Army, the army for the FS Area Operation, was promulgated by "Great army order no. 632" on 18 May 1942 and came into effect at zero hour on 20 May. This was the first time that a new operational army had been formed since the start of the war.
The order of battle of the 17th Army was as follows (the brackets indicate the unit’s previous association or location):
- 17th Army
- Commander: Lieutenant General Hyakutake Haruyoshi
17th Army Headquarters
35th Infantry Brigade (114th Infantry Regiment missing) (25th Army, southern Philippines)
- Commander: 55th Infantry Group commander
55th Infantry Group Headquarters
144th Infantry Regiment
55th Cavalry Regiment, 3rd Company (part strength) plus Rapid-fire Gun Squad
55th Mountain Artillery Regiment, 1st Battalion
55th Engineer Regiment, 1st Company plus materials platoon (part strength)
55th Division Signals Unit (part strength)
55th Supply and Transport Regiment, 2nd Company
55th Division Medical Unit (part strength)
55th Division, 1st Field Hospital
55th Division Veterinary Workshop (part strength)
55th Division Disease Prevention and Water Supply Unit (part strength)
47th Field Anti-aircraft Aircraft Battalion (type B, less one company) (14th Army)
- Commander: 2nd Infantry Group commander
2nd Infantry Group Headquarters
4th Infantry Regiment
2nd Reconnaissance Regiment, 4th Company (light armour)
2nd Field Artillery Regiment, 1st Battalion (motorised)
2nd Engineer Regiment, 1st Company plus materials platoon (motorised, part strength)
2nd Division Signals Unit (part)
2nd Supply and Transport Regiment, 3rd Company (motorised, one platoon)
2nd Division Medical Unit (part strength)
2nd Division, 2nd Field Hospital
2nd Division Disease Prevention and Water Supply Unit (half strength)
9th Independent Rapid-fire Gun Company (14th Army)
2nd Tank Regiment (one company) (16th Army)
20th Independent Mountain Artillery Battalion (23rd Army)
21st Field Heavy Artillery Battalion (one company) (25th Army)
45th Field Anti-aircraft Artillery Battalion (type B) (16th Army)
47th Field Anti-aircraft Artillery Battalion (type B, one company) (14th Army)
15th Independent Engineer Regiment (armoured) (25th Army)
4th Independent Engineer Company (heavy river crossing) (16th Army)
17th Army Signals Unit
- Commander: 17th Army Signals Unit commander
17th Army Signals Unit Headquarters
88th Independent Wired Company (motorised) (Southern Area Army)
3rd, 4th, 6th, 7th Independent Wireless Platoons (motorised) (16th Army)
33rd Fixed Wireless Unit (16th Army)
37th Fixed Wireless Unit (25th Army)
44th Fixed Wireless Unit (14th Army)
45th Fixed Wireless Unit (16th Army)
67th Line-of-Communication Hospital (16th Army)
24th Field Disease Prevention and Water Supply Unit (type B, part strength) (25th Army)
The South Seas Force, which had assembled at Rabaul, came under the authority of the 17th Army Headquarters as a result of this order. The South Seas Force was simultaneously strengthened with the 47th Field Anti-aircraft Artillery Battalion (two companies missing) from the 14th Army. One company from this unit had previously been transferred to the force.
The staging point for the main strength of the army was at Davao on Mindanao Island. Units would come under the authority of the 17th Army Headquarters upon their arrival at Davao. However, the 7th Independent Wireless Platoon and the 44th and 45th Fixed Wireless Units were ordered to proceed directly to Rabaul. They would come under the authority of the 17th Army Headquarters immediately on their departure from Hong Kong towards the Philippines.
The 17th Army command came under the administration of the Eastern Army Headquarters. It was ordered to form on 2 May, and this was completed at the Army Staff College on 20 May. On that day, "From zero hour, units not yet under army command will undertake administrative formations in preparation for operations."[26] The command of the South Seas Force was activated from that day.
The commander of the 17th Army was Lieutenant General Hyakutake Haruyoshi. He had transferred from the Army Signals Academy, and was therefore an authority on Japanese communications, especially regarding codes. The army chief of staff was Major General Futami Akisaburô, and the senior staff officer was Lieutenant Colonel Matsumoto Hiroshi.
The command of the 17th Army had no logistics-related units, only several lightly staffed bridge-building and military administration squads. Even so, the staff office had only three men. Further, the attack units were not organised as an offensive force, but a miscellany of units based on three infantry battalions. It would perhaps be more appropriate to call it a garrison army rather than an operational army. The critical defect was the lack of aircraft absolutely necessary for quality operations, especially the lack of aircraft needed for command coordination. Staff officer Matsumoto requested army aircraft for this purpose from the staff officer responsible for aircraft within the Operations Section in Imperial Headquarters, Lieutenant Colonel Kakemon Arifumi. His request, however, was denied because the Army Department wanted to rely on the navy’s air strength.
There was virtually no practical role for the 17th Army as an army. The army command could only fulfil a subjugation management role after landing.
Announcement of the army orders
Imperial Headquarters telegraphed the following orders to 17th Army Headquarters on the same day that the order of battle was issued:
- Great Army Order No. 633
1. Imperial Headquarters plans to invade key areas in each of the islands of New Caledonia, Fiji, and Samoa, and also to invade Port Moresby.
2. 17th Army Headquarters must cooperate with the navy to invade these key areas.
3. The army chief of staff will issue detailed instructions for these operations.
18 May 1942
The army chief of staff subsequently issued the operational outline on that day, as well as a central agreement concerning the operation.
The Navy Department of Imperial Headquarters also issued orders to the command of the Combined Fleet on 18 May. These ordered the Combined Fleet to "cooperate with the commanders of the 17th Army to invade key areas in the New Caledonia and Fijian islands and in the region of Samoa, and to smash main enemy bases in these areas". The Navy Department also issued instructions as follows:
- Appendix: Execute an invasion of the New Caledonia and Fijian islands and in the region of the Samoan islands according to the central agreement between the army and navy, and smash the main enemy bases in these areas. In addition, prepare bases at Suva and Noumea to control the waters to the east of Australia and blockade the line of supply between the United States and Australia.
The operation against Port Moresby was only mentioned in the new central agreement cited above.
Air operations were determined according to documents attached to the central agreement, as follows:
- 1. The navy will be responsible for air operations during the F and MO Operations.
2. The navy will establish airbases on New Caledonia, Fiji, and at Port Moresby. An airbase will be established at Samoa if it is to be secured and if the conditions are suitable.
3. For the present, 12 fighters and 12 carrier-based bombers will be deployed to New Caledonia. Elements of the 11th Air Fleet will be deployed for the Port Moresby operation. Units may be deployed to areas other than those specified above in response to operational requirements.
4. Army units in the area will cooperate to establish navy airbases and the execution of air operations.
- Great Army Instructions No. 1,153
Instructions
Instructions concerning transport along the line of communication based on "Great army order no. 633"
1. Munitions and matériel indicated in the chart below will be transported to the staging point for 17th Army operations, including weapons, approximately one engagement of munitions (in supply depots), three months’ fuel, and six months’ each of food supplies, clothing, necessities, medical supplies, and veterinary supplies.
2. Units which have transferred from the command of the Southern Area Army to the 17th Army will carry the following military supplies in addition to its full complement.
- a. Aoba Detachment
Approximately one engagement of munitions (including special munitions for landing operations)
15 inflatable boats
Four months’ signals consumables
Three months’ fuel
Four months’ each supplies, clothing, and necessities (including daily necessities and canteen goods)
Six months’ each medical and veterinary supplies
b. Other units
35th Infantry Brigade, 20 inflatable boats
One month each fuel, supplies, clothes, and medical and veterinary supplies
4. The army will plan to be completely self-reliant on the local area. Efforts will be made to reduce the amount of supply from rear areas.
5. The army will establish a Type-5 wireless and Type-1 anti-air wireless radio within six months and build a signals base at Rabaul. Local electricity and housing will be provided in key areas by the navy.
6. A signals network roughly according to attached diagram no. 1 will be established between the departure and arrival at the anchorage. A signals network corresponding to attached diagram no. 2 will be set up using the fixed wireless that will be established at the landing point.
7. The post-landing signals centre will broadcast as soon as possible after an appropriate determination by army headquarters.
The Type-5 wireless will be despatched to Rabaul after Tokyo receives communication that the above-mentioned signals centre has been completed.
8. A land-based fixed wireless must be established within four days from reaching the anchorage.
9. The execution of signals communication will be according to the appropriate sections of the "Army and navy central agreement relating to communications for the AL, MI, and F Operations", the "Imperial Headquarters Army Department communications rules", and the "Transport signals commander communications rules".
However, the Signals Unit of Imperial Headquarters will undertake communications such as is transmitted for special convoys or emergency transport signals.
The signals commander will issue further detailed directions.
10. Tents and established buildings will be used for the housing of troop horses. Do not expend much energy constructing new buildings for this purpose.
As a general rule, use materials found in the local area for construction.
11. Currency to be used by the army in the operations area will be as follows:
- NK area: military pound notes
Elsewhere: Japanese currency
13. A hospital ship shall accompany the main strength of the army to take responsibility for medical duties and evacuation of casualties during the landing operations.
14. Patients who require long-term treatment will be evacuated to Taiwan or Japan.
15. The commander of the Southern Area Army will grant line-of-communication functions to the 17th Army as required.
- Not only are your duties extremely important, you are conducting operations in areas that are essential to the enemy. Further, face counter-attacks with a fresh mind, and provide leadership to strive for completion of your new duties with equal amounts of caution and a vigorous heart.
- 1. Concerning New Caledonia
- New Caledonia is a French colony, and although it was placed under the control of the governor of French Indo-China, this is in name only. The island is governed in actuality by those loyal to the De Gaulle faction.
The situation in which the authority of the Vichy government is completely ignored is in no way related to the existence of a several hundred-strong garrison comprised entirely of local people with no military aptitude. According to recent intelligence, approximately 5,000 US and Australian troops have arrived on the island. This must be interpreted as an act of aggression. The Japanese army is invading at the request of the Vichy government. The Japanese operational mobilisation is purely in response to the actions of an enemy power.
Diplomatic relations with the Vichy government must be handled with discretion by the Japanese authorities. I would therefore like extreme caution to be taken to ensure that the operation is conducted smoothly, and especially that the operational plans are not disclosed prior to the event.
- New Caledonia
The centre of military government is located at Noumea in the south-west of the island. The main airfields are located in the south of the island. There is no reason to expect that enemy fortifications will be especially strong, so control of the centre can be gained with one fell swoop. For this reason, make plans to land in the south of New Caledonia.
Fijian islands
The Fijian Islands are British territory and are administered by the governor of the British South Pacific Colonies. There is also a garrison force of approximately 10,000 troops. The fact that it is also the centre point for the line of supply between the United States and Australia is particularly noteworthy. For these reasons, Fiji must be considered the most important location within the sphere of this operation and the main strength of the force must be used in this area.
The centre of military government is located on the main island of Viti Levu, so the objective of the operation can be achieved if this area is controlled first. It would be then sufficient to subsequently subjugate other islands such as Vanua Levu with elements of the main force.
Samoan Islands
Samoa is divided into Western and Eastern Samoa. Western Samoa is an Australian mandated territory and contains no garrison or visible military installations. Eastern Samoa is controlled directly by the US navy. For this reason, the important port of Tutuila in Eastern Samoa must be attacked first. After that, it would be sufficient to control Rose Island in Eastern Samoa (intelligence indicates an airfield under construction), and Apia, the capital of Western Samoa.
Port Moresby
Port Moresby has significance not only for being capital of British New Guinea, but for being an essential base of enemy operations (especially air) for the region. Much of New Guinea is undeveloped, so it is thought that the objectives of the operation can be achieved if Port Moresby and Kila airfield can be occupied.
Other islands
The navy has previously occupied the Solomon and Gilbert Islands.
The New Hebrides are jointly administered by Britain and France. The garrison and defences do not warrant concern in terms of mobilisation. The navy is expected to invade independently if the situation requires.
Tonga is a British protectorate governed by a local monarch, who at this time is a queen. The strength of the local garrison is not sufficiently strong to pose any problem. Further, it is hoped that good relations can be formed with the Tongans, and that there will be no necessity for the army to invade.
- The start of the operation is dependent on the circumstances of operations of the Combined Fleet. The army will continue preparations for deployment of its units for this operation. The navy will redeploy units currently operating in other areas. A judgment concerning the start of the operation will be made once the situation of other naval operations is made clear.
However, despite the start of the operation depending on the circumstances of naval operations, the navy central authorities must be canvassed if the start of the operation seems like being delayed much past the first weeks of July.
- In the case that military installations are destroyed and then troops withdraw after the invasion of Samoa, then the garrison will be manned exclusively by navy troops, though it is not possible at this time to indicate what the strength of this garrison will be.
Samoa, along with other islands, is located on the supply route between the United States and Australia. Even if Fiji and New Caledonia are controlled and Samoa is discarded, this will leave the air supply route from Hawaii through Canton Island and Tutuila to New Zealand. The army has argued from the beginning for the island to be secured in order to further the aims of strengthening the blockade between the United States and Australia. The Navy General Staff has argued for a deployment to the island of a contingent sufficient for the circumstances, or for the army to secure it alone in the interim. In either case, I hope that the enemy is in some way prevented from using the island, and that we realise the need to prepare for operations to well isolate the position.
If the overall situation requires the central authorities to issue instructions to abandon the island, then all installations, not just related to the military, must be completely and thoroughly destroyed. All civilians should be moved to other islands to make it difficult for the enemy to once again use Samoa as a base.
- The commander of the South Seas Force received imperial orders on 2 February to invade key areas in British New Guinea. This contained instructions consistent with the army and navy central agreement: "When possible, the army and navy will cooperate to invade Port Moresby." The army and navy authorities in the region began to carry out this operation in early May, but were delayed by losses in the naval battle in the Coral Sea. Gradually, the 17th Army began to undertake the operation.
In this way, the navy separately determined to undertake operations in the region, with a force based on the 2nd Fleet deployed in the New Caledonia, Fiji, and Samoa areas, and on the 4th Fleet in the Port Moresby area.
- Propaganda will be devised and executed by Imperial Headquarters under consideration of the entire Greater East Asian War.
- a. Concerning responsibility for military administration
This issue is under negotiation between subordinates of the army and navy bureaus of Imperial Headquarters. Even so, effort is being taken to recognise the appropriateness of the army having this duty, given its responsibility for military strength.
b. Concerning policies for the execution of military administration
Military administration contributes to the urgent need of securing a position of self-support for the army to attain the objectives of the war, in addition to restoring law and order and quickly securing resources vital for national defence. I would prefer preparations to achieve these to be based on "Great army instruction no. 993, appendix no. 1", "Outline of control of occupied territories following on from southern operations", "Army and navy central agreement relating to the execution of military administration in occupied territories", "Outline of army financial measures in the southern region", and "Outline of implementation of transport for the army in the southern region".
It is expected that instructions concerning the type and amount of raw materials vital for national defence will have already been issued.
c. Division of administrative duties by the army minister
The duties that must be allocated by the headquarters of the army minister will be administrative duties based on the fundamentals of military administration, and will be mobilised after the operation has been completed.
d. Various preparations for the execution of military administration
Five senior civil officials and essential clerical staff are currently being chosen as personnel for military administration.
Instructions will be issued concerning army and navy responsibilities for the development of mining operations on New Caledonia.
e. Concerning policies for New Caledonia
The execution of military administration of New Caledonia is on the surface problematic because it is French territory. However, as in other cases, it must be considered necessary to secure resources vital for national defence.
f. Details will be given to those responsible separately.
Army minister Tôjô also stated at this meeting that "The Samoa invasion must be carried out only by navy forces." The decision whether to secure or abandon Samoa was to be made immediately after the invasion. However, it was explained that this would place the occupation of Fiji itself in a very difficult situation, because in the case a force was to be stationed on Samoa, then it would be extremely difficult to secure Samoa without the participation of army troops.
Finally, army minister Tôjô indicated that he was opposed to using army air units in this operation. However, this did not become an issue as no air units were planned for the operation. This was primarily because the army minister held great concerns for air defences in the war of attrition in the Burma theatre and at Palembang.[28]
The departure of the 17th Army headquarters
The 17th Army headquarters were dissatisfied with their formation and the army’s order of battle. However, they had the full support of the Combined Fleet, which had achieved great successes since the start of the war, so approached the coming operation with optimism.
The 17th Army staff office had received news of the results of the battle of the Coral Sea and the cancellation of the South Seas Force sea-route invasion of Port Moresby prior to leaving Tokyo, but was relatively unconcerned. The Coral Sea battle had been a standard naval engagement, but the staff office considered it a great victory for the Japanese navy.[29]
The staff office did not feel that future battles would be any fiercer than previous engagements. Establishment personnel were insufficient, so female typists were employed. Complaints were issued by the assistant staff officer when they were allocated the code number "Oki 9802". The Japanese reading of this code suggested that they would "become swallowed by the open sea", so it was changed to "Oki 9811".[30]
The military deployment topographical charts given to the 17th Army headquarters by Imperial Headquarters were nothing more that civil topographical maps. Consequently, a survey of people residing in the area of the FS Operation was undertaken. Allied military deployments in the area were limited to those previously indicated by Imperial Headquarters. It was judged that only a small force made up of local troops would oppose them, providing very little resistance. Their only concern was for maintenance of supply.[31] Research into local self-sufficiency was consequently undertaken without waiting for instructions from Imperial Headquarters.
Preparations for issues of cooperation with the navy for the operation were undertaken solely by Imperial Headquarters. However, very few of the arrangements actually required, aside from some ceremonial matters, could be made in Tokyo. The only business remaining was to be completed by the navy at the Truk staging point.
As a result of investigations based on the operational outline provided to 17th Army headquarters by Imperial Headquarters, the following infantry group order of battle was issued:
- Fiji invasion operation
- 35th Infantry Brigade (with two battalions from the 41st Infantry Regiment attached)
South Seas Force
Samoa invasion operation
- Higashi Detachment (based on one battalion under the command of the 41st Infantry Regiment commander)
- Aoba Detachment
Imperial Headquarters had previously considered whether to strengthen the 17th Army with an anti-aircraft presence, and on 4 June, agreed to deploy two field anti-aircraft battalions: one battalion for the Fiji area, one company for the Samoa area, and the remaining two companies to New Caledonia.
Headquarters of the 17th Army planned to leave Japan after 10 June and proceed to Truk on the high-speed transport Ayatosan Maru. The commander and chief of staff left Tokyo in high spirits on 7 June by plane bound for Davao via Fukuoka and Manila.
Top of page
Cancellation of the FS Operation
The naval battle at Midway on 5 June ended in defeat for the Japanese navy. The effect of this defeat on the overall operational situation of the Greater East Asian War and war leadership was enormous. The operations in the South Pacific also were highly sensitive to the effects of the defeat. The FS Operation was initially postponed for two months, then cancelled outright. In addition, the Port Moresby invasion was switched from the sea route to the overland route.
Postponement of the FS Operation
The Operations Section of Navy General Staff summoned all staff officers at noon on 6 June and advised them that the four aircraft carriers Akagi, Kaga, Sôryû, and Hiryû had sunk, and that the main strength of the Combined Fleet was assembled behind the engagement line some 2,500 kilometres to the west of Hawaii. They added the opinion that the FS Operation should be delayed by at least two months.[32]
The countenance of chief of staff Yamamoto was grave as he announced the news. For the army chief of staff, this was a bolt from the blue. Chief of army operations, Tanaka, who had already known of the news, said: "We have lost supremacy in the Pacific through this unforeseen great defeat." The army chief of staff, Sugiyama, stated: "The two years of security provided by Admiral Nagano is smashed. We must choose a method outside of the Pacific region to lay low the enemy."[33]
At 4.40 pm on 6 June, the chief of staff of the Combined Fleet telegraphed the following to the chief of operations in the Navy General Staff:
- The Midway Operation has unavoidably been delayed. The prospects are that it will require two to three months in order to recover (mainly to the air strength). This will also flow on to delay upcoming operations. Negotiations will have to be undertaken again with the army concerning their cooperation in these campaigns.
The following day, 7 June, the Navy Department of Imperial Headquarters proposed to the emperor that the Midway Operation be cancelled. Orders to this effect were subsequently issued by the commander of the Combined Fleet. Agreement on direction of future operations was reached that afternoon in a research conference between the operations sections of the Army Department and Navy Department. The outline of this was as follows:[35]
- 1. The Midway Operation is cancelled for the present.
2. The start of the FS Operation is delayed for two to three months.
3. Research to determine how to secure the Aleutian Islands for the long term will proceed.
4. Research will be immediately undertaken to find out if Port Moresby can be invaded by the overland route.
That same day the Operations Section determined the following "Outline of managing the FS Operation in response to the conditions":[36]
- Policy
The F Operation will, for the present, be postponed for around two months.
The main strength of the F Operation units will assemble in Mindanao and Parao, with other units in the Bismarck Islands area. These units will exclusively make preparations and undertake training for the operation.
Transport ships allocated for the operation will be temporarily redeployed to other areas during the time of the postponement.
Outline
1. The army commander will depart (from Fukuoka on 9 June) as planned. However, the advance will be delayed from Davao, where unit command training will be carried out.
2. Army headquarters (less the commander) will leave port in Japan on 12 June as planned (on a 9,600 tonne hospital ship). However, the destination will be Davao, not Truk as planned (arriving in Davao on 20 June).
The various transport vessels will then proceed to Manila to be used for troop transportation.
3. The main strength of the 17th Army (35th Infantry Brigade, Higashi Detachment included) will remain on standby at their present locations at Cotabato and Cagayan. Although they are planned for redeployment with the Oki Group (17th Army), they will be used as transport troops to sail to Manila. An allocation will stay at Manila (arriving on 9 June) for use as transport vessels.
4. The Aoba Detachment will remain on standby at Davao, and exclusively undertake training at appropriate locations on Mindanao and Parao.
The allocation of shipping will be used to transport raw materials to Japan.
5. The South Seas Force will exclusively make preparations and undertake training at Rabaul and elsewhere.
6. The Ryôyô Maru (approximately 6,000 tonnes, 22 kilometres per hour) will stand by at Davao for the present; thereafter, it will transport the reinforcements (anti-artillery) and signals units for the South Seas Force to Rabaul.
These vessels will be available for use by the South Seas Force after completing these transports.
7. Those vessels to be used for the South Seas Force’s operations that are currently sailing from Parao to Rabaul (approximately 45,000 tonnes ballast, seven ships) will, for the present, stop and standby at Parao (due to arrive on 13 June). Thereafter, they will be transferred to the main strength of the Oki Group according to the need, and then used for troop transports to Manila.
8. The departure from Japan of military matériel transports (approximately 12,000 tonnes, three ships) bound for Truk will be postponed. The ships will be used elsewhere for the present.
9. The use of operational shipping for the F Operation during the postponement will be determined separately.
10. Take appropriate measures to cover immediate demands. For other items, report to Prince Takeda, who will be despatched to nearby Davao, then take measures.
On the following day, 8 June, the army and navy high commanders together presented to the emperor future measures to be taken following on from the operational changes. This took the form of amendments to the army and navy central agreements concerning operations in the Aleutian Islands and Midway, and the FS Operation.
Chief of Navy General Staff, Admiral Nagano, stated in the proposal to the emperor that the Midway Operation "should be postponed for the present as current conditions do not permit its adequate prosecution". Concerning the FS Operation, he explained that: "It was planned to start in early July. However, the operation should be postponed by about two months given the need to prepare reinforcements for naval air strength for Midway, and the unknown strength of our fleet."[37]
The commanders of the 17th Army were informed of these plans by a staff officer from Imperial Headquarters, Imoto, at Fukuoka on 8 June. The army chief of staff expressed his deep wish that the operation be carried out as soon as possible.[38]
The Army Department of Imperial Headquarters issued the following instructions to the commander of the 17th Army on 12 June:
- The execution of the F and MO Operations will be postponed. Elements of your force will assemble in the Bismarck Islands, with the main strength on Mindanao, and Parao if required, where you will prepare for future campaigns.
Cancellation of the FS Operation
The above measures taken in the South-East Area after the defeat at Midway were now completed. The Navy General Staff issued the following "Operational leadership policy for the area" on 13 June:[39]
- 1. Operations in the South Pacific Area
Operations carried out in mid-September
A land airbase must be established at Tulagi as soon as possible in preparation for the execution of operations (aim to have this operational by early August). Next, attack the land base in the New Hebrides and advance an air strength to the area.
2. Operations in the North Pacific Area
(The strengthening of Kiska and Attu has been omitted by the editor.)
3. Operations around Australia
- a. MO Operation
The invasion will be carried out, if possible, by the overland route. Commence and complete preparations as soon as possible.
The attack will be changed to a sea-route attack during the overland invasion if conditions permit.
b. Strengthen mainly submarine attacks against enemy shipping in Australian waters, and strengthen operations to smash the supply line between Australia and the United States.
(Attacks on enemy ships and the invasion of Ceylon omitted by the editor.)
5. Operations in the Central Pacific Area
- a. The timing of the AL and MI Operations will be determined according to the conditions and after special attack training is completed.
b. Seek an opportunity to adopt measures to entice and destroy the enemy fleet.
(Key points related to the Indian Ocean omitted by the editor.)
The first proposal (to attack New Caledonia, then Fiji and Samoa) had the advantage of nearby Japanese bases. The Allied base at Efate in the New Hebrides would be invaded and used as an advance base. However, there were fears that the Allies would then strengthen the defences at Fiji, but especially at Samoa. It was judged that if the invasion was undertaken within a month or so, the build-up would only be small scale.
The second proposal (to invade all three simultaneously) needed sufficient troop numbers to be effective. Though this was the preferred proposal, it had the disadvantage of dividing the strength of units. It was felt that difficulties could arise if the circumstances changed after pursuing several attacking fronts.
Proposal three (to attack New Caledonia after invading Fiji and Samoa) would strike through the Allies’ strongest point first. However, this proposal’s flaw lay in its dependence on air support from Japanese bases, and the unpredictability of that support being available.
Ultimately, it was decided that proposal one was still the most advantageous.[40]
The Combined Fleet returned to the western sector of home waters on 14 June.
The following day, Vice Admiral Itô Seiichi, assistant chief of navy staff, and other senior staff officers were despatched to the Combined Fleet to hold discussions concerning the new operations leadership policy. The Combined Fleet agreed in general to the points in the leadership policy, and came to an overall consensus concerning the reorganisation of the Combined Fleet.[41]
Incidentally, two Combined Fleet staff officers, Miwa Yoshio and Fujii Shigeru, visited Imperial Headquarters on 22 June. They strongly pressed for the cautious argument that the mobile carrier force should only be used against enemy sea units. There would be no uncertainty if airbase units were used at New Caledonia during the FS Operation. However, with no such certainty for the Fiji and Samoa operations, these invasions should be postponed and reconsidered. The staff officers also added that these were also the opinions of the commander of the Combined Fleet.[42]
The 11th Air Fleet sent its appraisal of the FS Operation to Imperial Headquarters on 30 June. This stated that the inability to utilise Zero fighters would be a difficulty for the campaign. (Zero fighters had an 87 per cent strike-rate, compared to 13 per cent for land-based attack planes in the air war of attrition in the South-West Area.) They further stated that if reinforcements to equipment and personnel could be supplied, then while the execution of the operation would not be easy, they were confident of success. However, because the attack on Moresby was to be undertaken before the FS Operation, the enemy air strength at the Port Moresby bases had to be dealt with. Consequently, the 11th Air Fleet proposed the following timetable for the execution of the campaigns:[43]
- Efate (New Hebrides): 20 September (day x)
New Caledonia: day x+15
Nandi (Fiji): day x+30
Samoa: day x+50
This proposal was adopted on 18 May, but contained points of fundamental difference with the operational outline mentioned above. This proposal was based on the idea that airbases would be successively advanced to cover a series of invasion operations within the sphere of air control.
Negotiations between the Navy Department and the Combined Fleet concerning subsequent operations reached a decisive stage on 5 July. At that time, staff officer Miwa forwarded the commanders the frank view that he would like the FS Operation to be discontinued. Further, he wanted the newly formed 3rd Fleet to be sent to the Canton Island area in the Phoenix Islands under the protection of Japanese airbases in the Gilbert Islands to lure the Allied fleet into a decisive battle. If the Allied fleet could be destroyed in this battle, then the FS Operation could be carried out quite simply.[44]
The Navy Department subsequently made the decision to temporarily discontinue the FS Operation.
While the navy was undertaking research for these various modified proposals, the Operations Section of the Army Department of Imperial Headquarters in the latter half of June was continuing preparations for research into overall plans for second stage operations, immersing itself in studies for the Szechwan Operations (the so-called Chungking Invasion Operation).[45]
The Navy’s Operations Section submitted to its army counterparts on 7 July the plan to temporarily discontinue the FS Operation. These documents provided a detailed explanation of the reasons for this decision, and are reproduced below:[46]
- Reasons why the FS Operation must be unavoidably discontinued at this time
1. With the current reduction of our carrier fleet, and learning from the lessons of the Midway battle, it is essential that Japanese air strength should smash and control Allied fleet air power in air battles within base invasion operations. These operations should follow on from the outlines of stage one operations in the southern area.
2. Concerning the F Operation, Allied air power should be destroyed first during the NK Operation at Efate (1,300 kilometres from Guadalcanal) and New Caledonia by base aircraft from the seaplane base at Tulagi and the land base at Guadalcanal (prospects for start in August), after which the airbase on Efate should be the object of a surprise attack. It is then essential to advance Japanese air units to Efate to neutralise Allied air power on New Caledonia.
Japanese air units at Efate and New Caledonia can then be used in the FI Operation to attack Fiji (Nandi is 1,000 kilometres, and Suva 1,100 kilometres, from Efate).
In the same way, units at the base on Fiji can then reach Tutuila at a range of 1,200–1,300 kilometres.
3. The 87 per cent success rate of Japanese air units against Allied air units in operations in the south relates to fighter planes. With the exception of the surprise attacks at the outset of the war, Allied bases within a range of 560 kilometres from Japanese bases are subject to attack. Fighters can also be used within this sphere. For the F Operation, New Caledonia can be attacked by fighters operating from a base at Efate. Operations must also be carried out by all medium attack planes and large flying boats within the limits of the range of offensive operations.
4. Under these conditions, and considering what has been learned to date, it is naturally difficult to expect to complete aerial destructive attacks using only medium attack planes. Furthermore, it is essential to use a force of troops absolutely superior to that of the enemy. Enemy fighters cause considerable damage during daytime air raids by Japanese bombers, but it cannot be ignored that damage during night raids will be reduced. Consequently, this operation should be undertaken with an air force of superior strength. It must be expected that attrition losses during the start of the campaign will be relatively high for an operation of this nature.
5. Consideration must be given to using carrier-based air strengths to compensate for the short-comings in these airbase battles. There is some uncertainty concerning Allied air strength in the area of the operation. There is no method to guarantee success in reconnaissance, but gradually increase strength day by day until the required amount of reconnaissance is reached. Further, ensure sufficient protection is given to aircraft carriers if they are to be mobilised. There is no suitable location for airbases, but on the other hand, the sea-route is extremely complicated, as the waters have not been sufficiently surveyed and movements are restricted. Failure to heed the dangers would herald dire consequences. It is therefore necessary to avoid the use of carriers where possible, within certain limits.
6. The campaign in New Guinea has developed into a war of attrition. The Allies have reinforced their air power at Moresby, particularly since the start of July (judged to be around 40 bombers). Their counter-attack after reaching full strength will tend to increase the attrition rate of Japanese aircraft. There is no argument over the necessity in overcoming the innumerable difficulties to invade Port Moresby as soon as possible. After the invasion, it will be difficult for the Allies to redeploy their air strength within the region. Losses will be high, but we must press on expecting a certain degree of reduction in strength.
However, reinforcements for losses in strength are, as will be discussed below, basically at a standstill, so numbers will decrease day by day. The large numbers of Zero fighters in the area will continue to attack the Allied B-17 and B-26 bombers, intending to hit their target with every shell. The current situation, however, is that we are unable to shoot them down. Recently, we have seen the appearance of the tragic situation whereby we are using our planes, as a last resort, as bombs to ram into the enemy. In the light of this situation, we have come to the conclusion that campaigns such as the F Operation are not a preferred option.
7. Approximately 400 carrier and land-based planes were lost during the Midway and Coral Sea battles. Various means are being investigated to reinforce and reorganise these strengths. In the past, even though production rates were low, they were increasing and losses to attrition could be replaced with a slight surplus. However, we are facing a huge challenge to cater for the scale of losses described above. In addition, there are no prospects that we will be able to increase production rates. The truth is that we have fallen into a huge rut. The situation at the end of June during the current campaign is that aircraft numbers for airbase units are 54 per cent below full complement for fighters, 37 per cent for reconnaissance planes, 75 per cent for medium bombers, and 80 per cent for flying boats. There are no prospects for this situation to be improved by reinforcements. On the contrary, the trend is that the situation will gradually worsen.
8. Current production rates for naval aircraft per month barely compensate for present attrition levels. Of particular concern is the disappointing production rate for fighter aircraft (less than 90 per month).
Neither are there currently prospects to restore operational strength owing to our reduced military capacity. There are grave fears that the intensification of the war of attrition at the front lines under the current circumstances may severely damage our ability to continue to prosecute the war. There are currently no prospects of increasing production levels. Because of this situation, we must debate emergency measures.
9. However, the enemy has temporarily suffered great damage in New Guinea and in the Port Moresby area from our aggressive attacks. Even so, they are extremely quick to reinforce their lines and mount counter-attacks. In contrast to our military strength, which is slowly being ground down, the enemy is able to freely maintain its strength. Japanese fighters are unable to mount very effective attacks against Allied bombers, who continue vigorous counter-attacks. If these conditions continue, the chances are extremely high that the Allies will gradually increase their strength until they have the numerical advantage and take complete control of the air war.
10. Taking all the above factors in combination, we should plan to postpone the current operation because of aircraft production levels, and take measures to make attacks against enemy bombers more effective. In the meantime, wide-ranging strategies should be debated, and planning undertaken to accelerate aircraft production levels. Only after these goals are met can we identify when it will be appropriate to start the operation.
Leadership for subsequent operations
In addition to the above-quoted "Reasons why the FS Operation must be unavoidably discontinued at this time", the Operations Section of the Navy General Staff also issued to the army "Instructions relating to the process of modifying the operational leadership policy". Appendix no. 3 of this document, reproduced below, contains a statement of the navy concerning subsequent operational leadership:[47]
- Operational leadership policy
1. The F Operation has for the moment been discontinued. The 17th Army and the 8th Fleet will invade Port Moresby as soon as possible. In addition, mopping-up operations will be conducted to remove enemy units remaining in British New Guinea. Take advantage of previously established airbases in key locations through air operations against Australia. Strengthen our counter-offensive standing against recovery operations that the Allies will be planning. In the meantime, proceed with research and preparations for the operation.
2. Occupy Nauru and Ocean Island and establish airbases. In addition, reinforce previously occupied airbases in the Gilbert Islands and intensify patrols in the region.
3. Strengthen operations to smash supply lines in the Indian Ocean using submarines and warships. In addition, intensify submarine operations to blockade transport along the line of communication between the United States and Australia.
4. Strengthen defences in occupied territories, and make preparations against enemy recovery operations that they will be planning.
5. The F Operation is planned to start sometime after December this year. This will occur after the completion of aggressive operations in the Indian Ocean to smash transport routes, after the development of air strengths in New Guinea following on the invasion of Port Moresby, after the increase in aircraft production, and after consideration of enemy strengths at that time. Operational preparations in key areas will be accelerated.
Explanatory notes
Concerning item 1
- 1. The cancellation of the F Operation has already been discussed in detail. The situation of the Allied troops in New Guinea must not be neglected. Installations and enemy land strengths must have been suitably strengthened in the light of reinforcements made by the Allies to the present. We must also assume that defence mechanisms also have been prepared, though we do not yet have accurate information to confirm this. Consequently, it is recognised that a vastly superior force must be used in order to attack these positions. It is therefore essential to completely clear Madang and Lae of the few remaining enemy troops, to invade Port Moresby, and to bring all of British New Guinea completely under Japanese control.
2. The fronts at New Caledonia and in the Solomon Islands must be secured. An appropriate number of airfields must be established in key areas in order to plan to advance southwards. In addition, effective army troops must be stationed to keep a sharp eye on the enemy and to maintain close contact and cooperation with the navy. It is essential to continue a wide range of research and preparations.
- Instructions have previously been issued concerning the occupation of Nauru and Ocean Island, though to date, this operation has not commenced. These areas are not only a source of phosphoric ore, but have the advantage of filling in the gap in patrols between the Solomon Islands and Marshall Islands. It is expected that the navy will undertake this operation independently.
- The campaigns to smash transport routes and shipping in the Indian Ocean, which flows from the sudden development of the war in northern Asia and the conditions of the war between Russia and Germany, are extremely effective when seen centrally as cooperative operations. Given the stage of the war overall, it is essential to quickly strengthen these effective measures also in terms of war leadership for Imperial Japan. If we were to undertake the F Operation, then our hands would be full for the rest of the year and we would be forced to abandon operations in the western Indian Ocean. If the F Operation were to be temporarily postponed, then we could mount large-scale submarine and fleet operations in this region, and even have a surplus strength. From the perspective of the overall war situation, strengthening operations to smash transport routes in the Indian Ocean is consistent with Imperial Japan’s war leadership policies in the region.
The reasons for cancelling the F Operation are also contained in appendix 2. As explained here, however, there are also considerations from the perspective of strategic leadership. This is because it is recognised that cancelling the operation will almost certainly be overall an advantage.
- The operations in the Indian Ocean are planned to continue until the end of this year. We must, however, have a fairly clear understanding of the war situation in New Guinea and of the military condition of the Allies through the results of reconnaissance in the F region. Further, we must make estimates of the prospects for aircraft production. We must take into account all of these conditions and look past the necessity or appropriateness of conducting the F Operation to recognise when it could commence. We are of the opinion that preparations should proceed to begin the operation after December this year.
We are of the opinion that there is a good likelihood of the F Operation going ahead in the future. With the exception of the drastic case of the possibility of an invasion of Australia, planning for the F Operation should not be entirely abandoned.
On the following day, 10 July, talks were held between the navy chief of staff, Admiral Nagano, and the army chief of staff, General Sugiyama. The main points of these talks were as follows:[49]
- Sugiyama: It is not a big issue if it can’t be done from the point of view of naval strength. New Caledonia is not of particular benefit. The essential places are Samoa and Fiji.
Nagano: The air war of attrition has only gradually intensified in the region of Moresby. This issue is being investigated by responsible officers of the army and navy. Our air strength is not all that stretched.
Sugiyama: There are rumours within the Allies that the Japanese will land on the coast and attack Moresby after the monsoon is over. Form units and reorganise munitions, etc., if you intend to mount an overland attack. Speed is of the essence.
It is expected that the commander of the 17th Army will make a decision concerning the overland attack at the beginning of August.
What’s the situation at Rabaul?
Nagano: There will probably be nothing more than the seaplane base. Current thinking is to spread our strength into the Indian Ocean.
This conversation between the commanders contains important hints of subsequent war and strategic leadership. It is evident that concerning attacks on Australia, the navy tended to apply its strength to the Indian Ocean rather than the Pacific, and that it was never confident of success in the blockade operation between the United States and Australia by means of the FS Operation. Of special note is the inauspicious appraisal of the future of the Rabaul base.
The statement of the army chief of staff contained a favourable account of the army’s continuing great interest in India and western Asia. This conforms to the aim at the opening of the war to break the spirit of the United States by first forcing Britain to surrender, rather than taking direct measures of this kind against the United States.
The preoccupation of the Army Department of Imperial Headquarters with research into the invasion of Chungking has previously been mentioned. Chief of operations Tanaka stressed either the importance of attacking Chungking with army troops and abandoning plans for a decisive naval battle against the United States somewhere in the Pacific, or the idea of joint army and navy incursions into India and western Asia to act in concert with Germany.[50]
At that time, the Japanese army’s domination of Burma was almost complete, and its pressure on India was intensifying. In Africa, it seemed that the German and Italian armies were sweeping all before them.
The Army Department and Navy Department of Imperial Headquarters decided on 11 July to abandon plans to restage the Midway Operation, and also decided to cancel the FS Operation for the time being. There were great expectations for the proposal that the FS Operation would be undertaken after December 1942. Later that day, Admiral Nagano presented these items to the emperor.[51] Orders were issued for the responsibility of the "Midway Operation and the invasion of key areas in the FS Region" to be taken from the commander of the Combined Fleet, and for the "Army and navy central agreement relating to the FS and Moresby Operations" to be scrapped.
On the army side, orders were issued on that day dissolving the duties of the Ichiki Detachment and ordering its formation to stand down after it returned to port in Japan. The following "Great army order no. 657" was also issued to the commander of the 17th Army:[52]
- 1. The responsibility of the 17th Army to invade key areas in New Caledonia, and the islands of Fiji and Samoa based on "Great army order no. 633" is hereby removed.
2. The commander of the 17th Army will cooperate with the navy to invade and secure Port Moresby, and to subjugate key areas of eastern New Guinea at an appropriate time.
3. Detailed instructions will be issued by the army chief of staff.
As mentioned above, the operational outline for the Port Moresby invasion was leaning towards the overland route. At the time, however, instructions for the operation were pending on the outcome of the Ri Operation research. This will be discussed in detail in the next chapter.
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Notes
1 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
2 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
3 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
4 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
5 Daihon’ei seifu renraku kaigi kettei tsuzuri (Decisions of Imperial Headquarters–government liaison conferences).
6 Daihon’ei seifu renraku kaigi giji roku (Record of discussions of Imperial Headquarters–government liaison conferences).
7 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
8 Ugaki Matome, Sensôroku (A record of war).
9 Fukudome Shigeru, Fukudome Shigeru Shôshô no kaisô (Recollections of Rear Admiral Fukudome Shigeru).
10 Fukudome Shigeru, Fukudome Shigeru Shôshô no kaisô (Recollections of Rear Admiral Fukudome Shigeru).
11 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
12 Daihon’ei seifu renraku kaigi giji roku (Record of discussions of Imperial Headquarters–government liaison conferences).
13 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
14 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
15 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
16 Nantô Taiheiyô Hômen kankei denpô tsuzuri (Telegrams related to the South-East Pacific Area).
17 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
18 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
19 Tomioka Sadatoshi, Tomioka Sadatoshi Taisa no kaisô (Recollections of Captain Tomioka Sadatoshi).
20 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
21 Maurice Matloff, Strategic planning for coalition warfare (Washington, 1953–59), p. 51.
22 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
23 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
24 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
25 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
26 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
27 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
28 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
29 Matsumoto Takeshi, Matusmoto Takeshi Chûsa no kaisô (Recollections of Lieutenant Colonel Matsumoto Takeshi).
30 Futami Akisaburô, Kodôki oyobi kaisôroku (Record of a beating heart and recollections) (1967).
31 Matsumoto Takeshi, Matusmoto Takeshi Chûsa no kaisô (Recollections of Lieutenant Colonel Matsumoto Takeshi).
32 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
33 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
34 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
35 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
36 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
37 Minami Taiheiyô sakusen shiryô (Documents of operations in the South Pacific).
38 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
39 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
40 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
41 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
42 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
43 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
44 Sanagi Kowashi, Sanagi Kowashi Chûsa nisshi (Diary of Lieutenant Sanagi Kowashi).
45 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
46 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
47 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
48 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
49 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
50 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Record based on the diary of Major General Tanaka Shin’ichi).
51 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
52 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Bundles of Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
Translated by: Dr Steven Bullard
Original text: Bôeichô Bôei Kenshûjo Senshishitsu (ed), Senshi sôsho: Minami Taiheiyô Rikugun sakusen <1> Pôto Moresubi–Gashima shoko sakusen (War history series: South Pacific area army operations (1), Port Moresby–Guadalcanal first campaigns) (Tokyo: Asagumo Shinbunsha, 1968): 119–166.
Reference for this web page: http://ajrp.awm.gov.au/ajrp/ajrp2.nsf/translation/Chapter3?opendocument
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