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Army operations in the South Pacific area: Papua campaigns, 1942–1943
Chapter 1: Offensive against Rabaul and key surrounding areas

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Chapter contents

Chapter 1: Offensive against Rabaul and key surrounding areas

Strategic issues concerning Rabaul

Basic preparedness for the offensive
Geographical description of Rabaul and the condition of the Allied forces
Operational preparations
The offensive
The conclusion of fighting
Consequences of the capture of Rabaul


      A convoy of Japanese forces landing craft set out for Rabaul, a key strategic site in the South Seas some 5,000 kilometres from Tokyo, at 11.40 pm on 22 January 1942.

      The flares launched by the Australian forces gave sharp focus to the white chop raised by the ships, as the crescent moon shone through the wispy clouds covering the ocean.[1]

      The curtain had been lifted on the desperate struggle that would continue for the next three years: 220,000 men of the Japanese army and navy were to be committed to the land operations in the South Pacific.

      The army had deployed the South Seas Force, based on the 144th Infantry Regiment of the 55th Division (from Shikoku), and the navy had sent the main strength of the 4th Fleet.

      Since the start of the war, Japanese operations in the south had progressed smoothly. By early January on the Malaya front, Japanese troops had advanced the best part of the way to Singapore, and had swept down to the strategically important Kuala Lumpur. In the Philippines, the capital Manila was completely occupied on 2 January 1942. Even in the Pacific, Guam had been occupied on 10 December and Wake Island on 23 December 1941. The invasion of Rabaul occurred within the context of offensives at other key areas in the South Seas, such as at Balikpapan on Borneo, Kendari in the Celebes, and Ambon in the Moluccas.

      The overall strategic superiority of the Japanese and Australian misjudgment of Japanese landing positions meant that the Rabaul operation went very smoothly.

      The navy occupied Kavieng on the north-west coast of New Ireland at the same time as the Rabaul offensive, and then attacked Surumi (Gasmata) on the south coast of New Britain.

      At that time, the forward observation line for the defence of Australia was considered to consist of Vila in the New Hebrides, Tulagi on Florida Island, the Buka Passage at Bougainville, Namatanai in central New Ireland, and Lorengau on Manus Island. The invasion of Rabaul and its surrounds breached this observation line, resulting in the immediate commencement of Allied aerial attacks on 24 January, the day after the landing.

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      Strategic issues concerning Rabaul

      Background to offensive operations in Rabaul

      The concept of adopting a defensive position and then luring the US fleet to an ambush and defeat in battle near Japanese waters had not altered as a fundamental strategy of the Japanese navy since the idea was formulated in the Meiji period.

      The waters near the Japanese mainland were initially chosen as the site of this decisive battle. However, advances in military technology and the changing strategic situation resulted in a re-evaluation in 1936 that moved the site to the seas west of the Marianas (with a reconnaissance line in the Marshall Islands). By 1940, the seas to the east of the Marianas and to the north of the Marshall Islands were the planned location.

      Focusing on this strategy, Truk Atoll in the Caroline Islands had become the major forward base for the Japanese Combined Fleet. Rabaul lay approximately 2,800 kilometres to the south in the Bismarck Archipelago, territory administered by Australia as part of the British Commonwealth. In the event of war with Britain and the United States, particularly with the development of the B-17, Japanese Imperial Headquarters became concerned that Truk would be vulnerable from attack by air units stationed at Rabaul. The occupation of Rabaul was therefore necessary to prevent this kind of attack and to ensure the safety of the fleet base at Truk.

      The Combined Fleet, the strike force for these operations and responsible for strategic campaign planning, realised the importance of air superiority, and viewed the campaign as a series of airbase offensive and defensive operations. The Marianas, Caroline Islands, and Rabaul were considered the main base line, so great importance was placed on Rabaul to support the extreme right flank of this line.

      Control of Rabaul would prevent its future development as an air and navy base to threaten Truk, and reduce the Allies’ ability to advance into the Solomon Islands and to the north coast of New Guinea.

      In this way, although there were minor differences of opinion between the Navy Department of Imperial Headquarters and the Combined Fleet concerning the strategic importance of Rabaul, there was absolute agreement as to the necessity of its occupation.

      Problems concerning the despatch of army troops

      In planning carried out in August 1941 for future operations in the southern area, the Navy Department of Imperial Headquarters had determined the strategic importance of occupying Rabaul in preparation for future battles against the US navy. The navy had strongly requested a combined force to undertake the initial offensive operation. Army high command realised the need for ground troops to support navy operations in this area, but considered that naval landing troops would be the most appropriate force. The army’s view, regardless of the importance placed on Rabaul, was that deploying army troops would be outside the scope of army force deployment. In particular, the assistant chief of staff, Lieutenant General Tsukada Isamu, strongly objected, saying that, "Deploying a small army force to isolated islands at the ends of the earth is like scattering salt in the ocean.”[2]

      Nevertheless, the "Bismarck Islands” were included as an essential area to occupy in the Imperial Army’s strategic plan developed in the case of war with Britain, the United States, and the Netherlands and presented to the emperor on 3 November 1941. According to the outline of strategic orders, "The South Seas Force will seek an opportunity to cooperate with the navy to invade Rabaul and seize its airfields.”[3]
        This outline clearly states not the "outbreak of war”, but "seek an opportunity”. Something had happened to change the army’s mind concerning the deployment of troops.

        Relation to the Malaya operations

        It was an unwritten law in the development of strategic planning following the outbreak of war that responsibility for operations on the continent lay with the army, in the Pacific with the navy, and that operations in the South-West Area would be shared. The army, which was responsible for the Malaya invasion, estimated on the basis of the conditions at the end of September 1941 that, owing to the air and naval strength of the Allies at Singapore, progress of the operation along the Malayan peninsula would be extremely slow. They concluded that it would not be possible for the 38th Division, which was in Cantong, to directly advance south to Sumatra before the units that would have left from eastern Borneo via the Java Sea. Consequently, as a result of the combined study meeting of staff officers from Imperial Headquarters and the 16th Army held on 28 September, it was proposed that the South Seas Force be sent to Palembang in Sumatra after its invasion of Guam, in order for units to reach the oilfield region as quickly as possible.[4]

        However, the navy, which had responsibility for the area, had planned to secure the oilfields at Miri (Borneo) at the start of the campaign. Further, they had strongly petitioned for Rabaul, Ambon, and Kupang (Timor) to be quickly invaded according to the progress of the war, but they did not have the required troop strength.

        As October arrived, further discussions resulted in the army and navy agreeing to cooperate. The navy would provide air units to hasten conclusion of the army’s Malaya operation. For its part, the army would send the South Seas Force to assist the navy’s invasion of Rabaul. However, modifications were made, with the South Seas Force to be transferred to the 16th Army (Netherlands East Indies invasion) after the completion of the Rabaul operation.[5]

        Editor’s note: Strategic plans for the South Seas Force’s invasion of Guam had been in preparation since 1923, so there was no problem per se with the deployment of army troops.

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        Basic preparedness for the offensive

        Formation of army units

        The formation of the South Seas Force, which had the fundamental responsibility for the Guam offensive, made steady progress while preparations and research were undertaken during the planning for the Rabaul offensive.

        Orders for the mobilisation of the South Seas Force were delivered on 27 September 1941, and were enacted on 1 October in Marugame in Shikoku. The force was to be led by the commander of the infantry group of the 55th Division, and was formed around one infantry regiment and one artillery battalion.

        Mobilisation was completed by 4 October. The main formation of the force is outlined as follows:[6]
            Commander: Major General Horii Tomitarô
              55th Infantry Group Headquarters
              144th Infantry Regiment (see note)
              55th Cavalry Regiment, 3rd Company (less one platoon) plus 55th Cavalry Regiment Rapid-fire Gun Squad (two machine-guns, one rapid-fire gun)
              55th Mountain Artillery Regiment, 1st Battalion (three companies, 12 guns)
              55th Engineer Regiment, 1st Company (four platoons) plus Materials Platoon (part strength)
              55th Division Signals Unit (part strength, two wired squads)
              55th Supply and Transport Regiment, 2nd Company (motorised)
              55th Division Medical Unit (one-third strength)
              55th Division 1st Field Hospital
              55th Division Veterinary Workshop (one-third strength)
              55th Division Disease Prevention and Water Supply Unit (part strength)
              47th Field Anti-aircraft Artillery Battalion (type B, one company)
              10th Independent Engineer Regiment, 3rd Company (less one platoon)
              Shipping Anti-aircraft Artillery Regiment (part strength)
              37th Anchorage Command (part strength)
              105th Sea Duty Company (one platoon)
              1st Shipping Signals Unit, 15th Platoon
        Lines-of-communication matériel, including one engagement of munitions, fuel, medical supplies, six months’ veterinary supplies, and five months’ food supply (including two months’ supply in transit) were issued from Hiroshima (except for clothing, which came from Sakaide).[7]

        The nominal strength of the force was 5,000 men, 1,000 horses, and 100 vehicles, with approximately 50,000 tonnes maritime transport required.

        Editor’s note: The 144th Infantry Regiment consisted of regimental headquarters, three battalions, an infantry artillery company, signals unit, and munitions squad. A battalion comprised three infantry companies, one machine-gun company (four guns), and one battalion artillery platoon (two guns). An infantry artillery company comprised two regimental guns and two rapid-fire artillery guns. A signals unit had a Type-5 radio (however, the regimental headquarters signals squad had a Type-3 radio).

        [Editor’s reference: One engagement of munitions is the basic amount presumed to be required for battle. While this amount will vary according to the circumstances, it generally includes 2,000 field mountain gun rounds, and approximately one thousand 15-centimetre howitzer and 10-centimetre machine-cannon rounds.]

        Navy preparations

        By October 1941, the army had agreed that the South Seas Force would cooperate with the navy in operations in the Central South Pacific Area.

        The navy unit responsible for these operations was the South Seas Fleet (based on the 4th Fleet) under the leadership of the 4th Fleet commander, Vice Admiral Inoue Shigemi. The 4th Fleet was formed in the fleet reorganisation of 1940 and given the main responsibility of the South Pacific Area under the command of the Combined Fleet. On 5 November, the duties of the 4th Fleet were contained in operational instructions issued to the Combined Fleet by Imperial Headquarters (Navy Department), as follows:
            Units based on the 4th Fleet will be responsible for the defence of islands in the South Pacific Area, for patrolling the region, and for protecting shipping transport routes. In the event of the outbreak of war, these units will invade Wake Island, and with cooperation from the army, invade Guam. When the opportunity arises, they will then attack strategic locations in the Bismarck Archipelago.

            Further, enemy forward bases in the South Pacific Area will be attacked and destroyed as deemed appropriate.
        The day after these instructions were received by the Combined Fleet, the following "Operational order no. 1” was issued to the South Seas Fleet:
            Stage one operational policy
              The South Seas Fleet will invade and destroy strategic locations in the region and make preparations against the enemy fleet in Australian waters.
            Stage one phase one: From the time of preparations to begin the war to 30 days after the landing of army troops in the invasion of the Philippines.
              4th Fleet Commander
              (stated below)
            Main responsibilities
              1. Defend and patrol the area of responsibility
              2. Invade Wake Island and Guam
              3. At an appropriate opportunity, prevent the utilisation of enemy airbases in the Howland Island area
              4. In response to the situation, invade Rabaul
            Operational outline
              1. As soon as possible attack Wake Island and Guam. In addition, patrol and defend the area of responsibility and prepare for mobilisation by the US and British fleets.
              2. (omitted by editor)
              3. Invade Rabaul and other key areas with the cooperation of the mobile carrier force according to the "No. 2 method for strategies against the US fleet”.

        [Editor’s note: The "No. 2 method for strategies against the US fleet” was a strategic measure of the Combined Fleet against the US fleet. In the case of the outbreak of war, and if the mobile carrier force has difficulty attacking the US fleet, then:
            1. Advance units (6th Fleet, mainly submarines) will observe the US fleet and undergo a surprise attack, and according to the situation, will attack the airbases at Howland Island, Tutuila, and Fiji, etc., with an appropriate force.
            2. The mobile carrier force (1st Air Fleet) will establish a strategic area in preparation for the US fleet.]

        Phase two of the operation was "up to 40 days after the completion of landing of army troops in British Malaya”. Phase three was "up to the completion of stage one operations in the Southern Area”. Main responsibilities were divided according to these phases.

        According to navy orders, it is clear that the object of Imperial Headquarters offensives was to secure key areas in the Bismarck Archipelago, while the Combined Fleet had indicated it had targeted Rabaul with the South Seas Fleet. The breakdown of the timing of the Combined Fleet’s "Stage one phase one” was different to that of the army.

        Announcement of the order of battle and instructions on preparations for the offensive

        The army issued "Great army order no. 555”, which outlined the order of battle of the South Seas Force, on 6 November, the day after the navy orders were promulgated.

        [Editor’s reference: The order of battle consists of the organisational, command, financial, and medical measures of the operational army issued by the emperor at the time of war or emergency.]

        The force commander, Major General Horii Tomitarô, presented himself to Imperial Headquarters on 8 November after receiving the orders. He was given the following instructions concerning preparations for the operations by the army chief of staff.

        Great Army Instruction No. 992[8]
            Instructions hereby given are based in Great Army Order No. 558.

              1. Preparations for operations of the South Seas Force will be in accordance with the South Seas Force commander. An outline of operations of the South Seas Force and central agreements of the army and navy concerning the operations of the South Seas Force are contained in the attachment.
              2. The South Seas Force commander will have preparations for the operation mostly completed by the end of November.
              3. Central Defence Headquarters will assist the anti-aircraft defence and patrolling of the South Seas Force in the Bonin Islands region using the defence units of that area.
              4. Plans in preparation for the execution of this operation will be kept in great confidentiality.
              6 November 1941
        Great Army Instruction No. 992 Attachment 1[9]
            Operational outline of the South Seas Force
              6 November 1941
              Imperial Headquarters Army Department

            No. 1 Operational objective
              1. To invade the strategic locations of Guam and the Bismarck Archipelago, and to suppress the menace of the enemy in the South Pacific islands area.
            No. 2 Operational policy
              2. The South Seas Force will attack Guam in cooperation with the navy, and then attack and secure the airfields at Rabaul when the conditions are favourable.
            No. 3 Operational leadership outline
              3. The South Seas Force will begin the operation after confirmation of the first air strike against the United States.
              4. The South Seas Force will, in cooperation with the navy, land and attack Guam.
              5. After securing Guam, its defence will be handed over to the navy. At an appropriate opportunity, the force will assemble at Truk and, with the cooperation of the navy, invade and occupy Rabaul on New Britain and secure the airfields.
              6. At the most opportune time, after this operation is completed, the force will hand over the garrison to the navy and assemble its strength at Parao.
              7. Landings will be undertaken in principle in the face of the enemy to sweep away the resistance of Allied army, navy and air forces.
            No 4 Operational outline
              8. Navy air units will begin operations at Guam after confirmation of air attacks on the Philippines.
              9. The South Seas Force, in readiness in the Bonin Islands, will land on Guam with the cooperation of the navy after confirmation of the first air strike against the United States.
              10. The main strength of the force will attack Apra Harbour from the rear after landing, while a part-strength force will occupy the capital, Agana. After that, pockets of enemy resistance will be mopped up.
              11. When mopping-up operations are completed, the garrison will be handed over to the navy. The South Seas Force will assemble at Truk under the protection of the navy and then make preparations for operations in the Bismarck Archipelago.
              12. In as far as the conditions of the naval protective force allows, the South Seas Force will, in cooperation with the navy, land in the vicinity of Rabaul in New Britain when the opportunity presents, and then proceed as soon as possible to attack and occupy airfields in the area.
              13. As soon as the situation permits after the completion of the occupation of Rabaul, the South Seas Force will hand over the garrison to the navy and assemble in Parao.
            No. 5 Staging points and transport
              14. The outline of transport and staging points following on from the execution of the operation will be carried out according to diagram 1. (Editor’s note: diagram 1 is not in the possession of the War History Office.) Great efforts must be taken to ensure that the staging and preparations for the operation are kept secret.
        Great Army Instruction No. 992 Attachment 2[10]
            Central Agreement of the Army and Navy Concerning the Operations at Guam and Bismarck
            6 November 1941
            Imperial Headquarters Army Department
            Imperial Headquarters Navy Department

            No. 1 Operational objective (Editor’s note: as above)
            No. 2 Operational policy (as above)
            No 3. Operation commencement
              The offensive will begin after confirmation of the first air strikes against the United States
            No 4. Operational outline
              1. At the beginning of the operation, navy air units in Saipan will attack and destroy enemy fleet defence installations on Guam.
              2. The navy will protect the transport of army troops to Guam and assist in landing operations.
              3. The main strength of the army force will attack Apra Harbour after landing, while elements of the force will occupy the capital, Agana. After that, pockets of enemy resistance will be mopped up.
              4. After Guam is secured, the army will hand over the garrison to the navy, and under their protection, re-deploy to Truk to prepare for operations in the Bismarck Island area.
              5. The navy will undertake aerial reconnaissance of the Bismarck Islands and carry out appropriate bombing operations.
              6. The army and navy will cooperate to invade Rabaul when appropriate and within the limits of naval protective capabilities. Further, the navy will occupy the airfield at Kavieng if the conditions are suitable.
              7. As soon as the situation permits after the completion of the occupation of Rabaul, the army will hand over the garrison to the navy and assemble in Parao.
            No. 5 Staging points
              The staging points are as follows.
              Guam operation: Bonin Islands
              Bismarck operation: Truk Island
            No. 6 Unit deployment
              Army: South Seas Force (based on three battalions from the 55th Infantry Division)
              Navy: units based on the 4th Fleet
            No. 7 Command
              The army and navy will cooperate.
              However, army and naval landing party units will be under the combined command of the officer with highest authority for operations on land.
            No. 8 Defence duties
              Appropriate arrangements will be made between the army and navy commanders in the area concerning defence on land.
            No. 9 Communications
              The navy will have responsibility for the army’s logistics liaison communications. All others will be in accordance with the "Army and navy central agreement concerning communications for Southern Area operations”.
            No. 10 Supply and medical
              The navy will assist as necessary with the transport of provisions and the evacuation of army casualties.
            No. 11 Operation date and standard time
              1. Date and time of the operation
              The date will be calculated from the commencement of Southern Area operations according to imperial orders.
              2. Standard time
              The time used will be Central Standard Time.
            No. 12 Command agreement between the army and navy
              The commanders of the South Seas Force and the 4th Fleet will enter into an agreement in Tokyo or another appropriate location as soon as possible after a determination is reached concerning the commencement of the operation.
            No. 13 Intelligence
              Intelligence will be collected by Imperial Headquarters prior to the issue of separate orders.
            No. 14 Operational names and strategic maps
              1. Operational names
              Guam operation: G Operation
              Bismarck operation: R Operation
              2. Strategic maps
              Indication of position will be according to exclusive military location maps.

        The following points are of great interest concerning these operations:

        1. The objective of the operation, namely "to invade the strategic locations of Guam and the Bismarck Archipelago, and suppress the menace of the enemy in the South Pacific islands area”, established a fundamentally defensive position for the operation.

        2. The scope of the operation was indicated to be from the time of the landing on Guam to the attack on Rabaul.

        3. The transfer from Guam to the Rabaul operation was modified by the expression, "as the conditions of the protective strength of the navy allows”.

        4. Command for this joint land and sea operation was shared by the army and navy. However, command for land operations was unified under the officer with the highest responsibility.

        5. After the completion of operations both in Guam and Rabaul, the army was to hand over responsibility to the navy and regroup in Truk and Parao respectively.

        Specific issues and modifications to these fundamental conditions will be addressed in the following chapters.

        Condition of the South Seas Force at the beginning of the Pacific War

        Following these executive instructions, the South Seas Force in cooperation with the navy, boarded nine transports and departed Sakaide Harbour in Shikoku heading for Guam. The force assembled and prepared for the operation in the harbours of Hahajima in the Bonin Islands on 28 November 1941.

        On 2 December while still in Hahajima, the commander of the force received a great army order concerning the start of the offensive operation. The force set out for Guam at 9 am on 4 December under the protection of the 4th Fleet. The convoy passed Rota Island en route, and began a three-way landing at around 2.30 am on 10 December. There was no large-scale opposition to the landing, and by mid-morning key areas of the island were occupied by the army and navy.

        On the same day, navy forces occupied Makin Island and Tarawa Island north of the Gilbert Islands. The attack on Wake Island had also begun without success, so the South Seas Force remained in readiness at Guam.[11] Later in the month, on 23 December, the second offensive against Wake Island was successful, after which preparations for the offensive against Rabaul began in earnest.

        Cancellation of the transfer of the South Seas Force to the 16th Army

        The army initially had problems using the South Seas Force for the Rabaul offensive. As stated earlier, the result of this was that "as soon as the situation permits after the completion of the occupation of Rabaul, the South Seas Force will … assemble in Parao”.[12] The plan was modified further so that the force would subsequently be transferred to the 16th Army, which was responsible for the invasion of the Netherlands East Indies. However, this transfer was cancelled during the planning stage owing to the following circumstances:

        According to the situation in November 1941, it was estimated that the South Seas Force would require at least forty days to invade Guam and Rabaul and then assemble in readiness near Parao. The Southern Area Army had greatly desired a speedy resolution to the southern operation, so it was not possible to anticipate only the advance of the South Seas Force for the invasion of Ambon and Kupang by around 20 January 1942. Consequently, it was decided in operational planning that "the South Seas Force and elements of the 38th Division” would attack in these areas.

        An agreement was subsequently reached on 14 November at the Iwakuni navy airbase by the navy’s Netherlands East Indies Force (3rd Fleet) and the 16th Army. It was decided that "as a general principle, Ambon and Kupang will be attacked with part of the 38th Division (B Detachment)”.

        The text of the agreement relating to the South Seas Force was as follows:
            3. The South Seas Force will assemble in readiness at Parao at x+40 days, and be transported to the main strength of the army at Camranh Bay as soon as possible.
            4. According to the circumstances, the South Seas Force will replace the B Detachment and land at Ambon and Kupang. According to strategic requirements at that time, elements of the B Detachment will be transferred from the Hong Kong area to Parao.
            In any event, this is agreed up to x+40 days. Command of the 3rd Fleet will be notified by the commander of the 16th Army.

        Incidentally, in the situation that had developed in the thirty days since the start of the war on 8 December, the 38th Division had landed on Hong Kong and progressed smoothly with the operation.

        In the Pacific Area, the South Seas Force had remained in readiness on Guam after the completion of the offensive operation on the island. Subsequently, the Rabaul offensive was inevitably delayed. This resulted in the 38th Division being given responsibility for the invasion of Ambon and Kupang.

        The staff of the Southern Area Army held a coordination conference in Saigon on 21 December with Colonel Hattori Takushirô, the head of the 2nd (Operations) Section of Imperial Headquarters. It was formally stated to the Southern Area Army that "the operation will not be altered even though the South Seas Force will not reinforce the 16th Army”.[13]

        It was through this transition that Imperial Headquarters terminated the transfer of the South Seas Force to the 16th Army. The effect of this can be seen in the issue of the following instructions:

        Great Army Instruction No. 1,068[14]
            This instruction is based on Great Army Order No. 584.

            1. Following on from the completion of the offensive against R, the commander of the South Seas Force will secure the area around [blank] regardless of the "Central agreement of the army and navy concerning the operations at Guam and Rabaul”. However, it should make preparations for redeployment to operations in other areas.
            2. The commander of the South Seas Force will transport part of its packhorse strength to Japan (including necessary handling troops) and temporarily place them under the 55th Division commander.
            4 January 1942

            Editor’s note: The [blank] in this text is presumed to be "R”.

        Although the actual text of this instruction was contained in several lines, its meaning was extremely significant. As stated above, the army had expressed some reluctance to despatch troops, but eventually agreed to proceed "to Parao after the completion of the Rabaul offensive”. The significance lies in the change to "secure the area around [Rabaul] … and make preparations for redeployment to operations in other areas”.

        Because the Southern Area Army had a surplus of troops, it would be easy to understand the cancellation of the transfer if the force was returned to Parao under the direct command of Imperial Headquarters. The placement at Rabaul under the command of Imperial Headquarters, however, given that the army itself had considered that "deploying army troops would be outside the scope of utilising army military forces”, meant that the army had changed its position. The reason for this change is thought to be as follows:

        The formal determination of the "Outline of future war leadership” that followed from the management of the offensive operations at the start of the Pacific War was in effect until early March 1942. The instruction to secure Rabaul was discharged on 4 January. The success of the navy’s attack on Pearl Harbor and operations in the sea off Malaya, and the speed of the army’s occupation of Hong Kong, Manila, and Malaya, were better than anticipated at the start of the war. The conditions of the war, such that the Netherlands East Indies operations could be advanced by one month, led senior staff officers to begin investigating operations against Port Moresby, which is the subject of a later chapter. These instructions, in the period prior to the issue on 2 February of official orders for the Port Moresby operation, must be seen in this context as preparations for the campaign.

        Consequently, because the merits and faults of this instruction leave the determination to invade Port Moresby and the "Outline of future war leadership” open to debate, they will be examined in more detail below.

        Offensive orders from Imperial Headquarters

        The following orders were issued to the commander of the South Seas Force on 4 January 1942, the same day as the above-mentioned instructions. He was busy at Guam with preparations for operations according to the prearranged plan.

        Great Army Order No. 584[15]
            Operational orders
            1. The operations of the Imperial Army and Navy are progressing favourably.
            2. The commander of the South Seas Force will cooperate with the navy and invade "r” as soon as possible after the middle of January.
            3. The chief of staff will provide detailed instructions.

            Editor’s note: It is presumed that "r” is an error for "R” (Bismarck Archipelago).

        Orders to the South Seas Fleet

        Meanwhile, the navy commander, Vice Admiral Inoue Shigemi, on 5 January issued "Top secret South Seas Fleet operational orders no. 7”, which outlined the invasion of Rabaul and other key strategic locations.[16]

        The disposition of units and main responsibilities according to this plan were as follows:
            1. R Invasion Force
            a. Main unit
              In cooperation with the South Seas Force of the army, invade the R region and destroy any enemy in the locality. In addition, establish a base for navy air operations.
              i. Protection of the army
              ii. Invasion of Rabaul in cooperation with the army
              iii. Establishment of a base in the R region
              iv. Defence of the R region
              v. Cooperation to provide navy air operations from the R region
            b. Detachment
              i. Invasion of Kavieng
              ii. Establishment of a base
              iii. Defence of Kavieng
              iv. Cooperation to provide navy air operations

        Orders were subsequently issued to units to assist the invasion force. These included support elements, submarine units, air units, and a mobile carrier force, etc., with the following responsibilities:
            Provide direct support for the invasion force
            Patrol and protect the St George’s Channel
            Destroy air capability in the Rabaul area
            Engage in operations against Australian air strength in New Guinea (including after the invasion of Rabaul), etc.
        Details of the strength of these units will be discussed below, but many of the aircrew that formed the main strength of the navy’s air flotilla had participated in the attack on Hawaii and were experienced and highly skilled.

        The unit responsible for the establishment and defence of the base after the invasion operation, as mentioned in the operation orders, was the same 8th Special Base Force that participated in the offensive. This will be discussed below.

        Formation and strength of navy units

        The formation and strength of navy units outlined in "Top secret South Seas Fleet operational orders no. 7” were as follows:
            1. Main force
              Command: 19th Squadron Headquarters
              19th Squadron (Okinoshima, Tsugaru, Ten’yô Maru, Mogamikawa Maru)
              6th Torpedo Squadron (Yûbari, 29th Destroyer Squadron (Oite, Asanagi, Yûnagi), 30th Destroyer Squadron (Muzuki, Yayoi, Mochizuki))
              Kiyokawa Maru, Kongô Maru, 5th Gunboat Squadron (Nikkai Maru, Seikai Maru)
              56th Submarine Chaser Squadron (No. 5 Kotobuki Maru, No. 8 Tama Maru, No. 3 Toshi Maru)
              14th Minesweeper Flotilla (Tama Maru, No. 2 Tama Maru, Hagoromo Maru, No. 2 Noshiro Maru)
              Maizuru 2nd Special Naval Landing Party part-strength, 7th Establishment Squad (Kôkai Maru, Takahata Maru), 5th Base Force 8-centimetre Anti-aircraft Unit (four guns)
              No. 2 Kaijô Maru, several fishing vessels
            2. Detachment
              Command: 18th Squadron Headquarters
              18th Squadron (Tenryû, Tatsuta)
              23rd Destroyer Squadron (Kikuzuki, Uzuki, Yûzuki)
              Kinryû Maru, Goyô Maru, Azumayama Maru
              Maizuru 2nd Special Naval Landing Party main strength, 5th Base Force 8-centimetre Anti-aircraft Unit (two guns), Kashima Naval Landing Party one company strength

        When divided into type, this force comprised three light cruisers, two minelayers, nine destroyers, two special cruisers, one special seaplane carrier, two special minelayers, two special gunboats, three special submarine chasers, four special minesweepers, and five other vessels.

        The main strength of the units cooperating with the invasion force included four heavy cruisers in support, six submarines, an air unit of 41 aircraft, and a mobile fleet based on four carriers (with approximately three hundred aircraft), two battleships, and two heavy cruisers.

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          Geographical description of Rabaul and the condition of the Allied forces

          Geographical description of Rabaul

          Considering the range of aircraft in early 1942, a 1,000 kilometre patrolling area centred on Rabaul would incorporate the Solomon Islands to the east, most of eastern New Guinea to the west, and half of the Solomon Sea to the south. New Ireland was draped over Rabaul to the north and extended towards the Admiralty Islands in the north-west. This was the sphere of activity at this stage. Within this, eastern New Guinea was an unfamiliar wilderness, and the Solomon Islands, Bismarck Archipelago, and Admiralty Islands were all isolated on the far edges of civilisation.

          This region was mostly covered with mountains, valleys, and dense jungle. Moss thrived in the shadows under the canopy of the huge trees. Level ground was flooded in time of heavy rain, and low-lying areas were boggy marshland. In addition to the climatic conditions of heavy rainfall and severe heat, diseases such as endemic malaria, dysentery, and tropical fevers were rife.

          Rabaul, the capital of the Australian Mandated Territory, was the only city in the region. With a population of around four thousand, the city was equipped with street lights and telephones. Rabaul was reached from the Australian mainland via the Coral Sea and served as the access route for Papua, Lae, Salamaua, the Bismarck Archipelago, and on to Truk. It was the primary communications route for Hawaii, Samoa, Fiji, the Solomon Islands, the Bismarck Archipelago, and Truk. Rabaul was consequently an excellent base for an operational army, and would serve as a route for an advancing force into the southern area. From the opposite perspective looking north, securing Rabaul would enable Truk to be attacked, and would threaten the various Japanese forces stationed on the left flank in the central Pacific.

          The strength of the Allied forces

          The strength of Allied forces at the time of the start of the offensive was judged by the Japanese from the available sources to be as follows:
              The enemy has despatched troops to key areas in New Guinea, the Bismarck Archipelago, and the Solomon Islands as one line in its stance against Japan. In addition to strengthening these defences, airfields continue to be established at Tulagi, Kavieng, Rabaul, Madang, Lae, Wau, Salamaua, Samarai, Port Moresby, and elsewhere.
          It seems that Rabaul is the enemy’s base of operations in the region, with a defensive strength of approximately fifteen hundred troops plus air units. Although there is no intelligence concerning Allied troops garrisoned at Kavieng, it seems that several hundred locals are undertaking patrolling duties, in addition to the establishment of an advanced airbase.[17]
            Concerning the Allied naval strength, it was determined that "although not confirmed, it seems that a strength of two A-class cruisers and four B-class cruisers from England, and two B-class cruisers from the United States have assembled in the southern waters of Australia”.[18]

            According to postwar investigations, the defence of New Guinea, the Bismarck Archipelago, and the Solomon Islands at that time was entrusted to Australia.[19] Consequently, the disposition of troops was as follows: the main strength of one Australian independent company, in addition to a native volunteer rifle unit, was sent to Bulolo in New Guinea (approximately 15 kilometres north of Wau). Part strength companies were advanced to Wau, Lae, and Salamaua, with detachments sent to Lorengau in the Admiralty Islands, Kavieng and Namatanai on New Ireland, Buka in Bougainville, and Tulagi on Florida Island.

            The garrison at the strategically important Rabaul was strengthened from March 1941. The disposition of troops by December was approximately as follows:[20]
                Commander: Colonel Scanlon
                Two companies from the 2/22nd Battalion of the 23rd Brigade
                New Guinea Volunteer Rifles (approximately 100 men)
                17th Anti-tank Battery (104 men including command)
                Two 6-inch naval guns
                Two 3-inch anti-aircraft guns (51 men including command)
                Royal Australian Air Force unit (ten Wirraway aircraft, four Hudsons)
                One squad from the 10th Field Ambulance
            The actual strength was around fourteen hundred men. From July 1941, however, an independent company under the command of a major had been stationed in Kavieng. In addition, it was judged that the troops stationed in Port Moresby had been reinforced by January 1942 to the following strength:
                One infantry battalion
                One 6-inch naval gun battery (two guns)
                One 3.7-inch anti-aircraft company (four guns)
                Numerous anti-tank guns
                Numerous aircraft
                This amounts to a total of approximately three thousand troops.

            When compared to the above-mentioned Japanese estimates, the number of troops despatched by the Japanese forces seemed adequate. However, what was significant is that the Allied coastal naval patrols, which were highly influential to the movements of forces on both sides, were probably not given adequate consideration by the Japanese. These coastal patrols provided "instant reports of discoveries of dubious happenings, suspicious vessels, floating mines, or other events related to the defence of the country”. Consequently, reports of the Japanese attack force, down to flights of individual reconnaissance planes, were delivered to headquarters in Port Moresby.

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            Operational preparations

            As previously noted, the South Seas Force spent approximately one month in Guam making preparations and undergoing training for the offensive against Rabaul. The cooperating naval force, the South Seas Fleet, made its preparations for the operation at Truk. There was sufficient time for preparations for both the army and navy after the completion of the offensive operation against Guam. There was an intimate understanding and mutual intent in the relations between the army and navy.

            Gathering of intelligence

            Although an outline of the climatic conditions and geography of the Rabaul area was known from pre-war intelligence, the South Seas Force had learned a lesson from the Guam offensive, which was unexpectedly difficult owing to insufficient reconnaissance of the landing sites. The South Seas Force coordinated with the navy to place army intelligence staff (Major Ikezoe Mitsunori of the 144th Infantry Regiment, which formed the main strength of the South Seas Force) on board navy reconnaissance flights. Major Ikezoe left Guam on 30 December and remained in Truk for about one week. Two reconnaissance flights were undertaken over the target area during this period. Major Ikezoe’s surveillance focused on:
                1. Placement and number of guns
                2. Placement and number of barracks
            3. The condition of obstacles in the area of the landing site.[21]
              It was felt that knowledge of the geography of Rabaul was understood sufficiently from pre-war sources. The purpose of the intelligence flights was to focus on the situation of the enemy.[22]

              Selection of a landing point

              The choice of landing site is the most essential element in a landing operation. There were three proposals for the location from the investigations, as follows:
                  Proposal 1: First land at Kokopo and secure a position, then invade Rabaul.
                  Proposal 2: Land on the northern coast to the west of Rabaul and attack Rabaul from the rear.
                  Proposal 3: Undertake multiple landings near Rabaul and attack from several fronts. Specifically, directly attack the township, attack the airstrip, and land on the coast between Tawui Point and Praed Point and directly attack along the main road to Rabaul.
              The condition of the landing site for proposal 1 was favourable, but English troops had landed at this part of the coast against German colonial troops during the First World War. Consequently, it was to be expected that this location would be heavily guarded and the advantage of the attack lost.

              The strategic strength of rear attacks made proposal 2 a strong plan. There was a high probability, however, of damage to the landing force from coral reefs when landing on the coast. It also seemed from reconnaissance that some artificial barriers had been erected. Furthermore, the plan was disadvantaged by early detection from scouts that would in all likelihood be positioned on Watom Island.

              The landing site for proposal 3 was suitable. The streets of Rabaul could possibly be approached from the blind spot between the artillery batteries at Tawui Point and Praed Point. However, a direct attack on the city and airfields of Rabaul seemed at first glance somewhat reckless. Further, there was intelligence that the ground to the west of the Lakunai (eastern) airfield had subsided and was covered with trees, making the arrival of landing craft difficult.

              As a result of an investigation into the advantages and disadvantages of these three proposals, the commander of the South Seas Force adopted a modified proposal 3: a three-pronged attack focusing on both airfields and the coast between Tawui Point and Praed Point. The aim of the commander’s plan was to exploit the lack of Australian numbers by attacking from all quarters so that the airfields could be quickly overrun before defences could be organised.[23]

              There is no documentary evidence for the intelligence evaluation on which the commander of the South Seas Force based this judgment of the situation. However, Major Toyofuku Tetsuo, who was attached to the force headquarters, recalled the situation as follows:
                  From the general lay of the land and position of barbed wire entanglements, the enemy had placed great stock in the dispositions in the coast at Talili Bay and near Nordup. It was judged that there was probably not a large strength positioned to the south of Raluana Point. In any case, if battalion strength was positioned defensively in Rabaul, then there would be a weaker deployment up to that point. Consequently, it was unknown whether or not they would suspect the location of the landing site and quickly mobilise troops to that area. (Editor: A short section has been omitted here.)

                  We felt that enemy air attacks on our convoy would most certainly come when we drew near to Rabaul. However, (owing to the lack of numbers) we didn’t expect to initially receive attacks from large formations while the fleet was still under way. Furthermore, we didn’t fear attack from enemy naval units because we had control of the sea at that time. It was suspected, nevertheless, that attacks would come from submarines.

              Agreement between the army and navy

              A detailed agreement with the navy, based on the "Army and navy central agreement” previously transmitted to the commander of the South Seas Force from Imperial Headquarters on 6 November 1941, was later arranged as follows:

              First, on 23 December, the South Seas Force chief of staff, Lieutenant Colonel Tanaka Toyonari, flew to Truk from Guam to undertake discussions with the navy concerning a preliminary agreement. Next, the commander of the South Seas Force, along with Chief of Staff Tanaka and the infantry regiment and battalion leaders, arrived in Truk on 4 January. The following day, the "Army and navy agreement for the offensive operation on Rabaul” was signed aboard the battleship Kashima with the commander of the 4th Fleet, Vice Admiral Inoue Shigemi. Further details of the agreement were established on 10 January aboard Yokohama Maru, at berth in Apra Harbour, through discussions with the commander of the 19th Squadron, Rear Admiral Shima Kiyohide, who had just arrived from Guam.[24]

              There were no fundamental differences of opinion stated in the deliberations for the agreement between the army and navy, and it seemed to progress smoothly, although no complete copy of the actual agreement survives. However, the content of the agreements on 5 and 10 January can be deduced to a certain extent based on the offensive orders of the South Seas Force on the army side, from extracts of the navy’s orders to the units involved in the R Operation, and from the surviving complete text of the agreement of the army and navy that was established for the invasion of Guam.

              Offensive orders for the South Seas Force

              As mentioned above, the commander of the South Seas Force received orders from Imperial Headquarters on 4 January to "cooperate with the navy and invade as soon as possible after the middle of January”. The main agreement with the navy was completed on 5 January, so the head of various independent units above battalion level were gathered in the former government offices in Guam and given "South Seas Force orders for the Rabaul offensive”.

              The main strength of the force would be deployed to attack Rabaul township and Lakunai (eastern) airfield. It was conceived that another strong force would occupy Vunakanau (western) airfield, while the main strength of the 144th Infantry Regiment, led by the regimental commander, would land between Tawui Point and Praed Point and invade along the main road to Rabaul from the coast. One detachment from this force would attack Lakunai airfield from the sea to the south of Praed Point. One infantry battalion directly led by the force commander would land to the south of Vulcan Crater and attempt to occupy Vunakanau airfield.

              An outline of the landing and details of troop dispositions for this complicated landing operation was delivered in instructions separate from these orders, along with documents outlining discussions resulting from the above-mentioned agreement with the navy. The landing operation orders issued to the regimental offensive group outlining the regulation and distribution of reinforcements and munitions, including discussion of how much food needed to be carried, was a model for landing operations, and is quoted below:

              Horii Operational Orders B, No. 34[25]
                  7 January 1700 hrs, Guam former government offices

                  1. The conditions at Rabaul are according to appendix 1 and actual aerial photographs.
                  2. The force will attack Rabaul.
                  The main strength will attack Rabaul township and Rabaul airfield, while another strong force will occupy Vunakanau airfield.
                    a. The operation will start at 1 am on 23 January. Operation plans are according to appendix 2.
                    b. Units from the navy will cooperate with the operation. The disposition of these units is contained in appendix 3.
                    c. The disposition of shipping transport units is contained in appendix 4. (Editor’s note: original document missing.)
                    d. Plans for air protection units are contained in appendix 5. (Editor’s note: original document missing.)
                    e. An outline of the landing is contained in appendix 6.
                    f. Sunrise, sunset, phases of the moon, and tides at the landing point are detailed in appendix 7 (abbreviated).
                  3. The Kusunose Unit and the Kuwada Unit will mobilise according to appendix 8.
                  4. The Disembarkation Duty Unit (exclusive use of small landing craft, armoured and high-speed) will be responsible for debarking the main strength of the force.
                  They will lead the disembarkation as follows.
                    a. The disembarkation unit related to each transport squad for the first and second landings will receive instructions from the commander of the front-line infantry unit (regimental or battalion commanders).
                    b. The transport vessels will move into Rabaul harbour after dawn as quickly as the artillery and aerial bombing situation permits, and then endeavour to proceed from the landing area towards the area of the Rabaul township.
                    c. Disembarkation at Rabaul should be undertaken at individual landing sites within the area where military strength is applied at the front line, at an appropriate time after ceasing hostilities.
                    d. All ships will be appropriately utilised after the second landing to strive for the most effective disembarkation.
                  5. The Cavalry Unit (less one artillery gun squad) will be used in reserve. Its main strength will land on foot with the force headquarters on the second and third landings and follow the headquarters in train.
                  6. The Supply and Transport Unit will proceed to the front line and cooperate with each unit at key locations.
                  7. The Field Hospital will supply a combat first-aid squad for each troop transport and be responsible for administering first aid to casualties behind the front-line units.
                  Emergency aid stations will be established on Clyde Maru and Venice Maru. Preparations will be made to accommodate casualties during the battle.
                  Preparations will be undertaken for a hospital to be established in the existing hospital facilities in Rabaul.
                  8. The Medical Unit will land behind the front line and will be responsible for housing casualties.
                  9. The Disease Prevention and Water Supply Unit will continue to land necessary personnel and equipment behind the front-line battalions and make key preparations to supply water to the front line.
                  10. The Veterinary Workshop will land following the disembarkation of horses and be responsible for providing them first aid.
                  11. Each unit indicated in articles 7 and 10 above will be given arrangements by the regimental commander for items directly related to front-line fighting.
                  Items not directly related to combat at the front line will be unloaded into the city after the transport ships return to Rabaul harbour.
                  12. Disposal of munitions in addition to formal equipment will be carried out by the infantry battalion commanders within the front line when necessary, as follows:
                    a. Engineer troops (amount to be used by one infantry battalion at the front)

                    Small flamethrower2
                    Medium inflatable boat5
                    Hand-thrown incendiary bomb10 (5 more for the Praed Point offensive unit)
                    Grenade launcher signal rocket (1935 model)10
                    Propellant smoke grenade50
                    Demolition charge 5
                    Akazutsu poison gas100 (Use prohibited unless special authorisation)
                    Hand-thrown gas canister100 (Use prohibited unless special authorisation)

                    b. Use only up to one-sixth of stocks of ammunition for infantry guns, grenades, and artillery.
                    c. Details of the amounts and transfer of these will be given by Lieutenant Tsurumi.
                  13. The landing party will receive the following provisions from the captain of the ship to be carried.
                    a. Two days’ supply of B field rations
                    b. Two lunch-box meals
                    c. Two packs of sweets
                    d. Each company and platoon will carry in addition two days’ supply of provisions
                  14. The code word has been determined as follows:
                    "South Seas victory”
                  15. The night signals for the first landing will be as follows:
                    Company commander and above, including regiment and battalion commander, white X-shaped sash on the torso.
                    Platoon commander, white sash from the left shoulder to right waist.
                    Squad commander, white band around left arm (10 centimetres wide).
                  16. My movements will be as follows:
                    a. I will be at the old government office, and will board Yokohama Maru at 12 noon on 10 January.
                    b. I will accompany the second landing on 23 January and then move according to appendix 8.
                  Force Commander Horii Tomitarô

                  Distribution method

                  Regiment commander and above will coordinate with all independent units and infantry battalion commanders. Commanders will gather and be given oral instructions, then written instructions to be distributed.
                  However, map names will be erased and kept secret. The landing date, as well as appendices 4 and 5 will be placed in sealed envelopes with orders to open after boarding and vessels are under way.
                  Editor’s note: Appendix 1 to these operational orders has been omitted by the editors.

                  Horii Operational Orders B, No. 34, Appendix 2
                  Operation timetable
                  4 JanArmy and navy agreement
                  5 JanArmy and navy agreementSubmission of personnel equipment certificates (1000 hrs)
                  Load condition inspections (1000 hrs)
                  6 JanArmy and navy agreementTransport headquarters inspection of vessels (until evening)
                  7 JanArrangements concerning load (0830 hrs)
                  Transmission of orders from transport headquarters (1500 hrs)
                  8 JanHorses on board and replacement load not includedVarious agreements following on from transmission of orders for offensive operations (from 1600 hrs)
                  9 JanHorses on board and replacement load not includedTransmission of orders to units directly attached to force (1600 hrs)
                  Transmission of battalion commander’s orders (continued from previously)
                  10 JanHorses on board and replacement load not includedSupplementary preparations for the army and navy agreement (1400 hrs, Yokohama Maru)
                  11 JanBulletin from the landing craft maintenance captain (0800 hrs, Yokohama Maru)
                  12 JanCombined training (from 1500 hrs 11 January to 0600 12 January)
                  Study group (Army: 1000 hrs, Yokohama Maru; Navy: 1400 hrs)
                  Fitting out of landing craft
                  13 JanLoading of horses, then loading of landing craft
                  14 JanForce commander’s instructions
                  Fitting out of landing craft
                  Supplementary preparations for operation

                  Horii Operational Orders B, No. 34, Appendix 3
                  Participating naval strength
                  1. Escort Fleet
                    Commander: Rear Admiral Shima Kiyohide
                    a. Main force (same as listed in "Formation and strength of navy units” above.)
                  2. Air units currently in Truk
                    Commander: Captain Yokoi Toshiyuki
                    Yokohama Air Corps, half detachment (14 large flying boats)
                    Chitose Air Corps, half strength (nine fighter planes, 18 medium attack planes)
                  3. Secondary escort units
                    a. Support Group
                    6th Squadron
                    Commander: Rear Admiral Gotô Sonshi (Aoba (flagship), Kinugasa, Kako, Furutaka)
                    b. Truk Area Defence Group
                    Commander: Vice Admiral Shigeizumi Shin’ichi
                    c. Saipan Area Defence Group
                    Commander: Rear Admiral Kasuga Atsushi
                  4. Cooperating Force
                    Commander: Vice Admiral Nagumo Chûichi
                    1st Air Fleet main strength
                    3rd Squadron half detachment

                  Horii Operational Orders B, No. 34, Appendix 6
                  South Seas Force landing operation overview

                  1. Overview
                  The arrival of the first landing group will be approximately 1.5 hours prior to first light. The main strength of front-line troops will be in the second landing group. Subsequent landings will build up the strength of these units, which will be at fighting strength before noon on that day.
                  2. Landing
                  a. The timing from entering the anchorage point to arriving at land will be as follows:
                  2300 hrs – enter anchorage
                  0000 hrs
                  0100 hrs – begin landing
                  0200 hrs
                  0300 hrs – arrive at shore
                  0400 hrs – first light
                  0500 hrs – dawn
                  b. The transport ships will range approximately 6 kilometres offshore to facilitate the boarding of landing craft (those landing within the bay will range to the east of the harbour).
                  c. The commencement of the landing will be enforced for each transport squad by the commander of the force, and by heads of infantry regiments and battalions.
                  d. Operation of landing craft will be organised into squads for each battalion in the first landing. Returning craft will operate individually.
                  3. Utilisation of transport vessels
                  Transport vessels will land at Rabaul harbour after daybreak as conditions under fire and mines in Simpson Harbour permit.
                  If the transport vessels remain under fire, they will be disengaged to a key distant evacuation point.
                  4. Liaison between the force command and the navy to facilitate the movement of the transport vessels for disembarkation will be the responsibility of Major Morimoto.
                  Movement of the transport vessels in response to danger or the situation of the enemy will be the prime responsibility of the navy in close liaison with the force command and Major Morimoto.
                  Movement of the transport fleet will be carried out as a rule by the lead vessel.

              Combined training

              The transmission of orders to lower units and various supplementary agreements with the army and navy followed for three days after the commander issued the offensive operational orders. Units were embarked during this time. Combined training between the army and navy was conducted from the morning of 11 January to the following morning on the seas off Apra Harbour. The content of this training was as follows: 1. Escort vessel formations; 2. Night landing craft operations.

              The seas were very rough during the night, so the transport vessels could not retrieve the landing craft. However, as the result of a joint study group during the morning, it was declared that "landing is achievable”.[26] The commander of the force gathered the various unit commanders and captains of vessels aboard Yokohama Maru the following day, 13 January, and delivered instructions for achieving the objectives of the operation.[27] The entire convoy was at anchorage in Apra Harbour with all preparations complete. All to be done was to wait for departure the following day.

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              The offensive

              Advance of the fleet transporting the South Seas Force

              At 1.30 pm on 14 January 1942, the nine ships of the South Seas Force transport fleet set out from Apra Harbour in Guam escorted by the navy and the main invasion force. The fleet was arranged in the "No. 3 defensive formation”, with the South Seas Force commander boarding Yokohama Maru as planned. The area had been patrolled in advance for submarine activity on 14 and 15 January by reconnaissance flying boats belonging to the 18th Air Corps of the Saipan 5th Base Force.

              While the weather on 15 January was cloudy, with fairly high waves, the following day was clear, with visibility to approximately 50 kilometres. On this day, the forward patrol had been taken over by the reconnaissance flying boat belonging to the special seaplane tender Kiyokawa Maru. On 17 January, at 7 am, Kiyokawa Maru rendezvoused on the western side of Woleai Atoll with the 6th Torpedo Squadron (less the 30th Destroyer Squadron) and the 4th Force (Seikai Maru, Kôkai Maru, and Takahata Maru, carrying the 7th Establishment Squad), which had arrived from Truk. Upon meeting, these units regrouped into a "No. 1 defensive formation”.

              Around this time, the following episode also took place: at about 6.25 pm, a mast was sighted on the horizon from the right deck of the warship Tsugaru, about 30 kilometres away. At first this was thought to belong to Yûbari, the leading ship of the 6th Torpedo Squadron, but at about 7.20 pm, the crew of Tsugaru realised that it belonged not to a warship, but a sailing ship.[28] Later, Captain Inagaki of Tsugaru recorded the following passage as an addendum in the margin of his detailed battle report:
                  At first, on seeing the sailing ship, we suspected it to be MacArthur fleeing from the Philippines to Australia in a small vessel, and pursued it with great excitement. As we put on more speed, however, our doubts increased, and finally upon catching up with the vessel, we realised that it was a Japanese fishing boat. For their part, the crew had believed themselves to be under pursuit from an American destroyer; and such was their relief upon finding out the truth that they gave us a rousing "Banzai”, and presented our crew with three or four tuna fish from their catch.
              Several clouds were scattered across the dawn sky on 18 January. The naval commander of the offensive force received a semaphore message from the commander of the South Seas Force, that stated: "Profound thanks for our naval escort. A ceremony is being arranged to mark our crossing the equator and your safe and speedy return to port.”

              Up to this day, the flying boats of Kiyokawa Maru had continued their advance patrolling of the route. Upon notice that the force had now entered the range of the Allied forces, the ships of the fleet now broke formation, spreading out to a distance of about 5 kilometres.[29]

              The morning of 19 January dawned cloudy, with a visibility range of approximately 40 kilometres. At 6.30 am, the regiment leader on board Cheribon Maru received the following message from Tsugaru, which carried the 2nd Squad, which consisted of the main force of the 144th Infantry Regiment:
                  1. The plateau to the north of the government office is defended by two high-angle anti-aircraft guns. The 2nd Squad is expected to infiltrate from an anchorage point beyond Laweo Point.
                  2. In the event that Tsugaru engages enemy artillery, command will be issued, depending on the circumstances, from Kongô Maru, and in extraordinary circumstances, according to the discretion of unit commanders.

              At 9 am, upon receipt of the message, the regiment commander signalled the following reply:
                  1. We plan to occupy the artillery positions to the north of the government office by dawn. The anchorage point for the 2nd Squad will be adopted as planned, paying attention to the battery on Tawui Point.
                  2. Anticipating that elements of the army force will attack the battery at Tawui Point by 4 am, the shelling of this area by the naval fleet will cease from that time onward.

              At 9.53 am, the captain of Tsugaru expressed his willingness to act as the regiment commander saw fit, provided no major damage was sustained by the transport fleet prior to the landing. This message was also relayed to the captain of Kongô Maru, but it is not recorded whether details of the coordination plan were acknowledged by the commander of the South Seas Force.[30]

              The morning of 20 January dawned cloudy, and at 5 am, upon crossing the equator, the force was in high spirits, proclaiming their achievement as "the first by an army formation since Emperor Jinmu”. As they approached Mussau Island, the fleet began to take precautions against their smoke being sighted from the island. At 5.30 pm, the destroyer Yûnagi detached from the formation in order to reconnoitre Mussau Island. In the afternoon of this day, the R Invasion Force detachment (based on the 18th Squadron) had left Truk Atoll for Kavieng.

              The morning of 21 January dawned calm and bright. At last, the fleet was drawing close to Rabaul, and at 4.40 pm, the South Seas Fleet (4th Fleet) issued the following wireless: "From approximately 1140 hrs on 21 January, until the afternoon, an enemy flying boat engaged the Japanese 6th Squadron.”[31]

              According to postwar sources, a message was issued from this flying boat stating only that "Four enemy cruisers are approaching Rabaul, from a position about 120 kilometres south-west of Kavieng.” Despite this, the New Guinea Area Headquarters at Rabaul decided that an attack must be imminent, and began to ready their troops for immediate action, including the despatch of emergency troops to man likely points of landing.[32]

              From the morning of 22 January, the task force could just glimpse the islands of New Britain and New Ireland despite poor visibility. According to the diary of Rear Admiral Shima, the commanding officer of the R Invasion Force, "The morning brought frequent sudden showers and dense cloud all around us. As we gradually drew closer to the coastline, we were very much worried about being taken unawares by the enemy. Indeed, it was truly by the aid of the gods that we were not troubled by them.”

              Meanwhile, the fleet approached its moment of truth, as the shady outline of New Ireland drew closer.[33]

              At 4.20 pm, the following signal was sent out by the flagship Okinoshima: "Tsugaru and the 2nd Squad will break with the battle formation according to plan.”

              Six hours later, all formations had arrived at their designated places of anchorage. The fierce north-westerly breeze, which had been a source of some concern, had dropped, and the sea was calm and quiet.[34]

              Air battles by navy air units

              Air operations at Rabaul and its surrounding areas can be divided into three basic types:
                  1. Operations carried out by the 24th Air Flotilla as the "Air Unit” according to unit formations made under "South Seas Fleet operational orders no. 7”.
                  2. Operations carried out by the 1st Air Fleet as the "Mobile Carrier Fleet” according to the same unit formations.
                  3. Operations carried out by a "Special Air Attack Unit” that was put together for this purpose by the Mobile Carrier Fleet.

              A summary of air operations, to place the land campaign within an appropriate context, is as follows:
                  1. The main task of the 24th Air Flotilla (composed of half each of the Yokohama Air Corps and the Chitose Air Corps) was the "complete destruction of enemy air power in the Rabaul area”. Their force consisted of a total of 41 aircraft: 14 large flying boats, 9 fighter planes, and 18 medium attack planes. The flotilla opened its campaign on 4 January 1942 after it received orders to commence reconnaissance and attack operations. The flotilla began bombing Rabaul with 16 aircraft on 6 and 7 January. On 9 January, while the flotilla was carrying out reconnaissance of the entire Solomon Islands region between Bougainville and Tulagi, it discovered two flying boats and their tender in the Buka Passage, as well as a medium flying boat in Tulagi Bay. Although the flotilla sent a unit to the Buka Passage the following day to attack and destroy the flying boat tender, it was unable to find the vessel. On 15 and 16 January, the flotilla carried out its fourth and fifth successive air attacks on Rabaul, and from 19 January, it expanded its reconnaissance and patrol duties towards the Solomon Islands and New Guinea.
                  2. It had been decided that the Mobile Carrier Fleet, which was based on the 1st Air Fleet, would cooperate with the attack on Rabaul by the South Seas Fleet under unit dispositions determined by the Combined Fleet for phase one of stage one operations. Their duty was the destruction of enemy air power in the New Guinea and Bismarck Islands region, as well as to patrol this region in advance of the invasion force. The unit reached Truk Atoll on 14 January, left it again on 18 January, and made the first attack on Rabaul on 20 January. A total of 109 planes took off from the aircraft carriers Akagi, Kaga, Zuikaku, and Shôkaku. From 11.45 am, the unit attacked the Rabaul airfield and the coastline for about 20 minutes, destroying oil tankers and five or six enemy aircraft.
                  On 21 January, a force of 52 aircraft from Akagi and Kaga advanced to attack Kavieng. Following this attack, a force of 46 aircraft launched a second decisive attack on Rabaul, but the response from the Allies was feeble.
                  3. The 5th Air Flotilla of the 1st Air Fleet (based around Zuikaku and Shôkaku) had been formed as a Special Air Attack Force whose task was to help destroy enemy air and naval forces at Lae, Salamaua, and Madang, and to provide support for operations in the Rabaul and Kavieng areas. The flotilla divided its 75 planes into two groups, which left the carriers at 9 am on 21 January. The planes attacked Allied installations, grounded aircraft and other vehicles at Lae, Salamaua, Bulolo, and Madang, and then returned safely to the carriers between 1 pm and 2.40 pm. Although the number of enemy aircraft was greater than expected, the unit sustained no damage apart from some return fire at Lae. There had been no counter-attack from Allied aircraft.

              Submarine operations were also carried out in coordination with the activities of the naval units. The unit concerned was the 7th Submarine Squadron (made up of the 23rd and 27th Submarine Groups), and it had been given the duty of patrolling and attacking enemy craft in the St George’s Channel. The squadron was in the St George’s Channel area for several days from 21 January, but, although it was prepared to encounter Allied shipping, no Allied warships were sighted during this period. The squadron therefore dismantled its formation; by the end of January all vessels had returned to Truk.

              Landing engagements

              During the above-mentioned air campaigns against Rabaul and its surrounding areas, the landing fleet was finally drawing close to Rabaul. The account begins with the activities of the 2nd Squad (Kusunose Unit) as it approached the first landing point:

              At 8.15 pm on 22 January, the order came to "Make preparations for landing.”[35]

              It was a dark, moonless night, although the stars sparkled brilliant in the sky. The tide was strong and swift. At 9.48 pm, two flares erupted from the black outline of the mountains of Rabaul, some 5–6 kilometres away. As their light died down, the order came to "Prepare to enter to the anchorage point.” At that time, the last boat in the flotilla, China Maru, had still not been sighted. On board China Maru were the main strength of the 4th Company and the Mountain Artillery Battalion, who were to occupy the battery at Tawui Point. Later, at 10.35 pm, the following order was distributed: "Proceed to the anchorage and commence landing operations.”

              China Maru had still not arrived, although the designated time had come and gone. The commander of the Kusunose Unit decided to proceed with only two landing craft. Landing barges began to be lowered into the sea from the transport ships from about 11 pm. Tsugaru left to search for China Maru.

              At 11.40 pm, the landing craft took off en masse. The officers and men aboard the barges seemed to glide across the surface of the water under the light of the flares. The mainland was still pitch black and the men were tense, shouting to each other, "Have you been attacked?”, "Are you under attack?” Light rising from the distant volcano and the burning streets of Rabaul reflected with a weird beauty into the night sky, making finding the way relatively easy.[36]

              Although the beach where the first wave of men came ashore was known as a "good place for landing, with a convenient beaching place”, in reality it was a 2–3 metre-high earthen cliff. Luckily, however, there was nobody about. Dense forest immediately behind the cliffs made discovery of Three Ways extremely difficult. After 30 or 40 minutes of searching, the unit located the road and set out towards the mountain pass.

              It was about 5 am and the dawn was well advanced when, having overwhelmed the small band of Australian soldiers who were stationed at the pass, the Japanese troops occupied the former governor’s residence, located on the saddle between The Mother and South Daughter. The tardy China Maru had rejoined the formation at about 4 am, and the 4th Company proceeded swiftly to the landing area of the main force. They advanced to Tawui Point by about 6.20 am along the northern coastal road, but did not find the artillery battery. There had been a native hut about the same size and shape as an artillery battery, but it had been reduced to rubble by the naval bombardment.

              The 3rd Squad (Kuwata Unit) followed the Kusunose Unit. The Kuwata Unit, whose duty was to occupy Vunakanau airfield, was led into the berthing by Nikkai Maru at 10.30 pm. The unit completed preparations and began landing at 12.18 am. The main force of the Kuwata Unit (based on the 3rd Infantry Battalion) was expected to advance directly to Vunakanau airfield from the shore to the south of Vulcan. The 8th Company was to land near Raluana and take up a position on the left flank of the main force to cover the advance to the airfield.

              There were low hills stretching beyond the shore, and no landmarks could be identified at night. This made it extremely difficult to confirm the designated landing points. For this reason, the 9th Company ended up straying to the north of Vulcan. The battalion commander, however, simply assumed that the 9th Company was heading for Vunakanau airfield after his main force had managed to reach the designated landing point. He was anxious to occupy the airfield without delay so as to prevent Allied aircraft from taking off and bombing Japanese troops. The problem was that the route identified on photographs was covered in jungle and could not be located. Unavoidably, the troops advanced behind engineers cutting a path through the jungle.

              Meanwhile, the 9th Company faced serious resistance after landing on the north shore of Vulcan. Wire entanglements were set on the shore. The Australian official war history stated the following: "The Australians could see the landing craft and their occupants silhouetted against a boat and dumps ablaze in Rabaul harbour and township .... As they landed the Japanese were laughing, talking .... We allowed most of them to get out of the boats and then fired everything we had.”[37]

              The 9th Company moved southwards because of this counter-attack, avoiding the front of the Australian positions. There were many gorges to cross. As soon as the Japanese attempted to assemble, the Australians began firing machine-guns and mortars. The Australians were targeting the signal shots that indicated assembly positions.

              The main strength of the battalion was advancing through the jungle. The commander mistook the gun shots from the front of the 9th Company for those from Rabaul township where the 1st Battalion was mounting an attack. Day broke while the battalion was in the jungle, after which they finally reached the road on the central highland.

              Given the task of occupying Raluana, the 8th Company had landed according to plan and driven out the small Australian force by 2 am to take control of Raluana Point. The 8th Company then despatched a platoon to occupy Kokopo.

              The main strength of the Kuwata Unit encountered Australians troops withdrawing from Rabaul, as well as those retreating from Raluana Point under the attack of the 8th Company. The 7th Company was pivotal in these battles, unexpectedly encountering Australian troops on three occasions. At 1.15 pm they broke through to Vunakanau airfield.

              Occupation of the Praed Point battery

              The 1st Battalion of the Kusunose Unit, aboard the transports as the 1st Squad, entered the anchorage at 10.20 pm charged with the task of occupying the Praed Point battery and Lakunai airfield. The Praed Point battery was equipped with ten artillery guns. The Japanese therefore planned to move the entire convoy back a further 5 kilometres from the shore if Praed Point was not occupied by 4 am owing to the danger of the battery attacking the transport convoy. The commander of the 2nd Company, while heading for Praed Point onboard the transports, was told: "If you cannot occupy the battery by 4 am, then you must cut open your bowels and die!”[38] The 2nd Company advanced at 1.20 am at the head of the main strength of the 1st Battalion, and reached the landing point 1,500 meters to the west of Praed Point as planned at 2.10 am. There were some wire entanglements in place, but no Australian troops were present. The 2nd Company advanced along the coast to the east and found two destroyed 16-inch artillery guns near the point. They frantically scoured the area for the other eight guns. Time was quickly running out.

              The designated time of 4 am passed without South Seas Force headquarters receiving notification of the success of the operation. The commander of the naval invasion force ordered all vessels to "move to the special anchorage position”. The commander of the South Seas Force considered deploying the reserve unit, a cavalry company, at the front of the 1st Battalion, so ordered his troops to prepare for a second landing. Soon after the order had been communicated, however, three white signal flares rose from the slopes of South Daughter. As members of the force headquarters breathed a sigh of relief, the naval commander issued the order for the "convoy movement to cease”.[39]

              In actual fact, the front-line company, unwilling to give the signal without confirmation, had searched around for the remaining seven or eight artillery emplacements suggested by intelligence. It turned out that there were not ten but only two guns in the area and that the information provided had been wrong.

              The main strength of the 1st Battalion advanced to the eastern shore of Matupi Island without the anticipated resistance, and the 3rd Company was deployed to the western shore. Meanwhile, as shots were continuously fired down on them from Vulcan, the battalion commander decided at 5 am to lead the 3rd Company towards Rabaul township.

              Leadership by the commander of the South Sea Force and support from the navy

              The commander of the South Seas Force had anticipated a great deal of resistance. He recognised the enemy’s planes flying over the area and flames like signal flares on the ground at the time when Yokohama Maru had led the 1st Squad of the transport convoy into the anchorage.

              The first landing units went ashore and the commander received radio communication and signal flares reporting successful landings from all fronts at about 2 am. The front of the main strength of the Kusunose Unit was quiet. The sound of heavy fighting could be heard for some time from the direction of Praed Point prior to the report that the artillery battery had been occupied. After the capture of Praed Point, the commander moved from Yokohama Maru to a barge with the cavalry company.

              The weather on 23 January was fine. The sound of gunshots from various fronts stopped with the rising sun. The commander of the South Seas Force assumed that the situation of the battle had proceeded favourably. At 5.28 am, he decided to advance the cavalry company to the western shore of Rabaul harbour in order to intercept the Australian’s retreat from the township.

              The force commander arrived at the eastern shore of Matupi at 5.30 am. After communicating an order for all ground units to be transported to Rabaul township, he again boarded the barge and headed for Rabaul. On board he heard gunshots from the area to the north of Vulcan. While disembarking at the second pier of Rabaul harbour, he saw a cavalry company courageously landing in that area under a rain of fire that poured down from Vulcan.

              The force commander proceeded to Rabaul township in search of the location of the commander of the 2nd Battalion. The commanders met near the western edge of the township. The force commander received briefings on the situation of the 2nd Battalion and the cavalry company. He then returned to Chinatown, where he met the commanders of the infantry regiment and the 1st Battalion, who provided him with more information concerning the battle. At just that time he received the following telegram from the Kuwata Unit:
                  Sent 8.20 am. Main strength of the 3rd Battalion currently engaging enemy troops retreating from the airfield at Three Ways to the north of Mt Seto (the central high ground). The situation around the airfield is unclear.

              This prompted the force commander to order the regiment commander to deploy the 1st Battalion by barge from Rabaul harbour in order to assist the 3rd Battalion.

              The 1st Battalion left Rabaul harbour at about 11.00 am, landed on the shore to the south of Vulcan, and advanced to the airfield via Raluana. They found out on the way that the airfield had already been captured by the 3rd Battalion, so the 1st Battalion decided to assemble to the east of the airfield to prepare for future operations.

              The naval carrier fleet despatched a total of thirty carrier-based fighters and 18 carrier-based bombers between 4.30 am and 2.45 pm. These provided aerial protection for ground offensive units and reconnaissance on the Australian’s positions. Vessels at sea contributed to the landing operations by liaising with ground units and clearing the sea around the harbour.

              The disposition of the Australian army</a>]

              The situation of the Australian garrison in Rabaul was changing as follows:

              The commander of the garrison, Colonel Scanlan, was informed that a Japanese convoy was heading for Rabaul and that Kavieng had been attacked. He issued the following orders in the afternoon of 21 January:
                  1. Move all troops from the camp to the west of Rabaul, which is in an exposed position.
                  2. Send an improvised company under the command of a captain to Raluana to prepare for a landing by Japanese troops.
                  3. Prepare other companies for movement but inform troops that it is "an exercise only”.

              Colonel Scanlan ordered these changed dispositions to prevent losses from naval gunfire and bombardments on the assumption that a Japanese strength would land within Keravia Bay. The third order, however, later inflicted mischief on his men, as some of them went into action without essentials like rations.

              Early in the morning of 22 January, the Australians sent their only remaining plane to Lae via Gasmata and buried more than one hundred bombs in the runway to destroy Vunakanau airfield. As discussed above, the Japanese navy’s dive bombers had completely destroyed the Praed Point battery by 6 am.

              With the destruction of the Praed Point battery, the evacuation of the air force, and the cratering of the airfields, Scanlan decided that the garrison could no longer fulfil its responsibilities. He subsequently ordered the destruction of all military facilities and withdrawal from the township of Rabaul.

              An engineering unit was sent to destroy a bomb dump in the town at 2 pm. The blast from the explosion shattered all the valves of wireless sets in the telegraph office in Rabaul, as well as damaging the radio transmitter at headquarters. As a result, the only means of communications with the outside world was via a teleradio that had been set up at Toma (6 kilometres south-east of Vunakanau airfield).

              Colonel Scanlan judged that the main Japanese landing would take place within the harbour. He therefore moved his headquarters to the central highland, moved his front-line troops to the established camp on the west coast of the harbour and moved the reserve units to the area around Four Ways.

              The redeployment of all units to their new positions was completed by 3 pm. Most civilians were being evacuated by transport vehicles, cars, or on foot along the road leading to Kokopo. Columns of black smoke rising from the heavily bombed Rabaul township darkened the sky over their heads.

              The improvised company deployed to Raluana finally completed establishing its position by 9 pm. With no time to pause for breath, the Australians prepared to face the Japanese landing.

              The heaviest fighting occurred on the coast to the north of Vulcan in front of the established camp. Communications had broken down after 12.30 am between the front-line troops and the battalion commander, as well as between the battalion commander and Colonel Scanlan. The Australian commanders could only hope that front-line troops provided brave resistance. The garrison commander temporarily moved the reserve unit from Four Ways to prepared positions 2 kilometres east of Vunakanau airfield and ordered them to cover the Kokopo Ridge Road.

              The improvised company in Raluana began to retreat at 1.45 am. At dawn the units located on the north of Vulcan also began withdrawing. At 4.45 am, Colonel Scanlan decided to move his headquarters to Tomavatur.

              After daybreak Japanese naval aircraft repeatedly dive-bombed and strafed the entire battlefield. The telephone line between the reserve unit and battalion headquarters was cut at 6.15 am. From then until 10 am, fierce battles were fought by stubbornly resisting Australians and ever infiltrating Japanese in areas between Three Ways and Taligap. When the garrison commander decided that it was useless to prolong the action, he ordered the northern companies to withdraw to Keravat River, the southern to Warangoi River, and both to hold these positions as long as they could. This virtually meant that organised resistance by the Australians had come to an end.

              Naval offensive operations at Kavieng

              The commander of the South Seas Fleet planned concurrent attacks on Rabaul and on Kavieng, New Ireland, using the R Invasion Force detachment (based on the 18th Squadron). He ordered this on 5 January, as previously discussed.

              According to general information and reconnaissance by a navy flying unit, blackouts were not enforced in Kavieng, and there no signs that the airfield had been recently used. It was confirmed that Kavieng was guarded by a few hundred native soldiers and some patrol officers, but no information was available regarding the Australian reinforcements and military facilities.

              The Kavieng Invasion Force left Truk on 20 January.

              Air units began bombarding Kavieng on 21 January, resulting in most ground facilities being burned down. The invasion force approached the designated landing place during the evening of 22 January using this smoke as a guide. Units designated for the western shore effected a successful landing at 2.30 am on 23 January and secured the airfield. Kavieng township was completely occupied by 4 am. The eastern shore units effected a successful landing at around 4.40 am.

              Neither party encountered either Australian soldiers or local civilians. The Australians had attempted to destroy the airfield by igniting aircraft fuel immediately after the Japanese came ashore, but the runway was repaired within a few days to the extent that fighters could safely take off and land.

              Investigations after landing revealed that nine Australian commissioned officers, including a Major Wilson, and about two hundred servicemen had been stationed in Kavieng and surroundings. They were said to have fled to the south-east at the time of the 21 January air raids. Local residents gradually returned to Kavieng after the Japanese had occupied the island.

              Naval landing troops completed mopping-up operations on the island on 24 January, and swept through Namatanai and neighbouring islands such as Ambitle Island, Mussau Island, Tabar Island, and Djaul Island between 25 and 28 January.

              Imperial Headquarters’ announcement of military achievements

              Imperial General Headquarters made the following public announcement at 5.15 pm on 24 January:
                  1. The Imperial Army and the Imperial Navy, working in close cooperation, eliminated the enemy’s resistance and successfully landed in the Rabaul area of New Britain in eastern New Guinea before dawn on 23 January. They are steadily extending their gains.
                  2. A special naval landing party of the Imperial Navy made a successful opposed landing at Kavieng in New Ireland before dawn on the same day.

              The comment attached to the announcement emphasised the significance and effect of the operation as follows:
                  Rabaul and Kavieng, which were the front positions of the Australian defence, formed the most important part of the strategic communication line of Britain and the United States between their enveloping positions against Japan before and during the Greater East Asian War.

                  The successful capture of these areas has not only brought the destruction of British and American strategic positions but also gained us the advantage of using these positions to establish an airbase in the South Pacific and to extend our control of the skies from the western Pacific into the south Pacific. The capture of this important position, from where it will be possible to spread our influence to the Australian mainland, is extremely significant in terms of our ability to attack and menace Australia.
              The United States is currently desperate to secure a strategic line linking the United States and Australia, while endeavouring to defend the Dutch East Indies and Singapore in cooperation with Australia. However, the successful capture of Rabaul and Kavieng makes it possible for the Japanese to occupy the sea around New Zealand, and increases the possibility of blockading the line of communication between the United States and Australia.[41]

              Whether Japan was actually able to cut the line of communication between the United States and Australia as envisaged in the above statement, and whether Japan gained the absolute advantage in the war in the South Pacific, will be discussed in a later chapter.

              Pursuit by the South Seas Force

              The following describes the situation of various units of the South Seas Force during the afternoon of 23 January.

              The main force of the regiment (based on the 2nd Battalion), which had landed between Tawui Point and Praed Point, advanced to the western outskirts of Rabaul and was engaged in clearing out the township and surrounding areas. The 4th Company, despatched to occupy the battery at Tawui Point, joined the main force at about 1 pm after making a detour along the western shore of the peninsula. The 3rd Battalion occupied Vunakanau airfield and was in the process of mopping up the surrounding area.

              The 1st Battalion was transported from Rabaul by barge to assist the 3rd Battalion and assembled at Vunakanau airfield.

              The force commander ordered an "initial thorough clearing of the surrounding area”, so assigned the Kusunose Unit (the regiment main force) to the high ground to the west of Vulcan, and the Kuwata Unit (based on the 3rd Battalion) to the area between Vunakanau airfield and Kokopo. The clearing operation began on 24 January.[42]

              The following day, the force commander concluded from the compiled intelligence that the Australian forces consisted of five infantry companies under Colonel Scanlan, one heavy artillery company, one anti-aircraft artillery platoon, and others, including approximately fifteen hundred servicemen. The commander became aware that the main Australian force had retreated to Ataliklikun Bay, and that elements had fled to the south of Kokopo.[43]

              The commander also found that all Japanese civilians had been sent to Sydney in the middle of January.[44] The commander led the movements of all units, aiming to mop up the Rabaul area and quickly repair the airfield according to the pressing duties of the force. When the initial cleanup was completed, the navy requested "a thorough clearing of the area as it is unknown when the army will be redeployed”. As a result, the army decided to undertake a thorough pursuit from 27 January.

              On 26 January, planes sent from the special tender Kiyokawa Maru discovered five small ships in Open Bay and one ship in Wide Bay. The main strength of the regiment then was sent to Ataliklikun Bay to conduct a pursuit attack, following the Australians along the coastline. They crossed several rivers by building temporary bridges, but jungles and swamps beyond the Vudal River impeded their advance. They had no choice but to continue the pursuit by boat. The pursuit party cleaned up major coastal points up to Lassul Bay on 28 January under the protection of a destroyer. The forces suspended the pursuit and returned to Rabaul in the evening of 29 January after the rain had made passage through the coral reef dangerous.

              The force completed the clearing operation in the northern half of the Gazelle Peninsula by the end of January.[45]

              Meanwhile, the Japanese received intelligence indicating that the majority of the Australian forces were still in the forest to the north of Wide Bay. In response to the suggestion from the 3rd Battalion commander, the South Seas Force commander deployed a company for pursuit along the coast line to Put Put Harbour, and the main strength of the 3rd Battalion to Wide Bay by sea. They left Kokopo on 2 February and carried on the pursuit as planned during 3 and 4 February.

              The Australian garrison commander, the former governor-general, and others were captured during this operation, which completed the clearing and pursuit campaigns. The troops were then deployed in defensive positions on a line to the north of the Warangoi River and the Keravat River.

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              The conclusion of fighting

              Direct military results

              It had become clear by 10 March that the Australians had suffered the following in damage and lost matériel:
                  Killed in battle: approximately 300
                  Prisoners: 833
                  Aircraft: 8
                  Battery guns: 2
                  Anti-aircraft guns: 2
                  Rapid-fire guns: 15
                  Mortars: 11
                  Machine-guns: 27
                  Light machine-guns: 7
                  Rifles: 548
                  Armoured vehicles: 12
                  Cars: 180
                  Motorbikes: 17
                  Armoured boats: 3
              In contrast, the Japanese losses were:
                  NCOs and enlisted men killed in battle: 16
                  Officers wounded: 3
                  NCOs and enlisted men wounded: 46
                  Horses killed: 4

              Allied planes appeared in the night skies over Rabaul every other day after the offensive operation against Rabaul commenced on 23 January, bombing transport vessels and ground units. The damage inflicted (not including damage to the navy) up to 5 February was as follows:
                  Killed: 4
                  Wounded: 18
              Damage to transports: slight[46]

              Establishment of an airbase

              When the airfields around Rabaul were occupied, it was discovered that the facilities were insufficient, and they were not in a condition to be used immediately owing to damage inflicted during the invasion. Further, there were substantial discrepancies from what could be determined from intelligence photographs.

              The situation after 23 January was as follows: the ground at Vunakanau airfield was soft and the airstrip was uneven because it was situated on high ground. Consequently, it was not suitable for large planes to take off and land and required paving for medium bombers. A work party of approximately one thousand men was quickly despatched from various units to assist the navy’s 7th Establishment Squad. In addition, it was decided that a detachment of army engineers would provide assistance to hasten the repair effort. Furthermore, the road between the disembarkation point and the airfield was long and steep, and the terrain was also a liability.

              It was expected that fighter planes would be able to use Lakunai airfield by 25 January. Further, expansion works and logging of required lumber was planned to be completed by mid-February in anticipation of the advance of 18 medium bombers. Buoys were positioned and repairs undertaken to the timber refuelling jetties in the expectation that approximately twelve seaplanes would be able to use the harbour base at Rabaul.[47]

              The commander of the 8th Special Base Force, Rear Admiral Kanazawa Masao, who had planned to mobilise on 1 February, disembarked at Rabaul with his staff during the afternoon of 23 January. The commander took leadership of the airfield repairs by the 7th Establishment Squad and other units on 26 January based on the "Operational support for the 19th Squadron” instructions.

              Seaplanes (those onboard Kiyokawa Maru and Okinoshima) began using the harbour base from 24 January, while fighter planes (from the Chitose Air Corps Rabaul Detachment) first advanced to the Lakunai airfield on 31 January.

              It was possible for land-based attack aircraft (24th Air Flotilla 4th Air Corps) to advance to Vunakanau airfield from about 10 February.

              By 20 February, a total of 51 aircraft, including 18 land-based bombers, 18 carrier-based fighter planes, nine flying boats, and six reconnaissance seaplanes, had been assembled at the various airfields around Rabaul.

              Orders for a new naval formation</a>]

              The commander of the South Seas Fleet issued the following orders on 29 January after the completion of offensive operations in Rabaul:
                  1. Operations will be conducted according to the following third order of battle from midnight on 1 February:
                    The Rabaul Invasion Force is dispersed and the Rabaul Area Force formed (command and disposition) as indicated below.
                    8th Special Base Force Headquarters
                    8th Special Base Force, 6th Torpedo Squadron, 14th Minesweeper Flotilla, Tsugaru, Kiyokawa Maru, Kinryû Maru, Kashima Special Naval Landing Party, Combined Air Unit (Kashima, 17th Air Corps Detachment), 7th Establishment Squad, Kôkai Maru, Takahata Maru, 4th Construction Detachment Establishment Squad, 4th Supply Detachment personnel, 105th Air Workshop Detachment personnel, 8-Centimetre Anti-aircraft Unit (5th Base Force Detachment) (Editor: The following section has been abbreviated.)
                  2. The area of responsibility for the 4th Base Force and the 8th Special Base Force extends to the equator.

                  3. Units will mobilise according to the second order of battle and existing responsibilities under operational orders, in addition to the following.
                    a. Bismarck area units
                    i. In addition to quickly constructing the airbase at Rabaul, the Surumi area will be invaded as soon as possible and an airbase established.
                    ii. In cooperation with the army, efforts will be made to mop up enemy strengths in the Rabaul area.
                    iii. Transport routes will be secured in addition to guarding and patrolling the assigned defensive maritime region.
                    b. (Editor: The following section has been abbreviated.)

              The navy units responsible for the defence of the Bismarck area were formed as a result of the issue of these orders. Further, these orders were responsible for the speedy development of the airbase at Rabaul. The 8th Special Base Force Headquarters assumed responsibility from the 19th Squadron for guarding and patrolling the Rabaul area based on these orders of 1 February.

              Meanwhile, the 24th Air Flotilla, under the command of the South Seas Fleet, assumed command of the newly formed 4th Air Corps and advanced to Rabaul on 14 February.

              Violent outbreak of malaria</a>]

              There was a violent outbreak of malaria during the clean-up operations at Rabaul, especially during the pursuit of Australians in Ataliklikun Bay. Almost the entire 1st Infantry Battalion was afflicted to the extent that it was not possible to post sufficient sentries. Neither was it possible to transport the large numbers of patients with high fevers to hospital. Despite efforts to administer treatment on the spot, many soldiers perished. The physical exhaustion of the survivors had a significant impact on the outcome of later battles. Many cases of malaria emerged within the 3rd Battalion in the Kokopo area, but these were few compared to the 1st Battalion. The least affected was the 2nd Battalion in Rabaul.

              The importance of anti-malarial measures in tropical warfare was underscored from the beginning of the campaign. Despite the use of anti-mosquito headgear and gloves, and the administering of preventative medicine, the reasons for such a sudden outbreak are thought to be as follows:

              1. The majority of officers and men had no experience of tropical warfare, and while they had received some instruction in the dangers of malaria, the reality of these dangers had not sunk in.

              2. The complete absence of malaria during the Guam offensive naturally put them off their guard.

              3. When large numbers were afflicted, the senior officers and medical staff, most of whom specialised in infectious disease prevention, were initially unable to diagnose malaria.

              Concerning this last point, because the diagnosis of tropical malaria was not made until several days after admission to hospital, some of the afflicted seemed to deteriorate into a state of madness.

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              Consequences of the capture of Rabaul

              The Japanese invasion of Rabaul and key surrounding areas was intended in planning at the beginning of the war to provide an advance base to protect the naval base at Truk, and to develop the air strength on the flank during a decisive battle. The successful completion of the operation saw the realisation of these aims for the present.

              The Allied uncertainty as to how to stop the Japanese juggernaut after the defeat on the Malayan peninsula and the loss of Rabaul began to impact greatly on the citizens of Australia. In fact, the general mood in Australia at that time was one of extreme alarm.

              Four well-trained divisions, plus a New Zealand division, were all serving overseas with the best officers. Defence of the huge expanse of the Australian coastline was absolutely impossible by either sea or sky. With the hope of protection from Great Britain gone owing to rising tensions in Malaya and the Middle East, Australia could only look to the United States for assistance.[50]

              On 14 February, the US army minister responded by sending the 41st Infantry Division for the defence of the Australian mainland. Transport of the approximately twenty-five thousand troops of the division, including support elements, could not be undertaken, however, until the period from mid-March into early April.[51]

              The Allied force was faced with a crisis in early February as to how to cover this deficiency. Admiral Leary, the commander of the ANZAC area of responsibility established as an interim emergency command area, initially considered bombing Rabaul from the recently reinforced Lexington Task Force and by B-17 raids from the Australian mainland.[52]

              The changing conditions and responses to the Rabaul invasion by both armies during mid-February will be discussed below.

              Regardless of the propriety of the campaign, it was a model offensive operation conducted on a distant island.

              It could be claimed that the army and navy cooperative operational outline established at the beginning of the campaign was ideal when seen from any of its elements: the strategic bombing prior to the invasion, the protection of the transport fleet, support for the landing operation by tactical air groups, and the advance of the land and naval forces.

              With the exception of the Fire Support Coordination Centre (FSCC) established later by the US army for the Guadalcanal offensive, the outline of Allied counter-offensive operations after mid-1942 was largely conducted from a strategic perspective according to the operational model of the Japanese armed forces.

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              1Toyofuku Tetsuo, Toyofuku Shôsa kôwa (Interview with Major Toyofuku Tetsuo).
              2 Tanaka Shin’ichi, Tanaka Shin’ichi Shôshô no nisshi ni motozuku shuki (Notes based on the diary of Major General Tanaka Shin’ichi); and Okamura Masayuki, Okamura Masayuki Shôsa no kaisô (Recollections of Major Okamura Masayuki).
              3 Sakusen kankei jûyô shorui tsuzuri (Important documents related to operations).
              4 Okazaki Seisaburô, Okazaki Seisaburô Shôshô no kaisô (Recollections of Major General Okazaki Seisaburô).
              5 Imoto Kumao, Imoto Kumao Chûsa nisshi (Diary of Lieutenant Colonel Imoto Kumao).
              6 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              7 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              8 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              9 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              10 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              11 Toyofuku Tetsuo, Toyofuku Shôsa kôwa (Interview with Major Toyofuku Tetsuo).
              12 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              13 Arao Okinori, Arao Okinori Chûsa nisshi (Diary of Lieutenant Colonel Arao Okinori).
              14 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              15 Dairikumei, Daikairei, Dairikushi, oyobi Daikaishi no kakutsuzuri (Great Army Orders, Great Navy Orders, Great Army Instructions, and Great Navy Instructions).
              16 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              17 Sakusen kenkyû shiryô (Operations research documents).
              18 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              19 Dudley McCarthy, South-West Pacific – first year: Kokoda to Wau (Canberra: Australian War Memorial, 1959, p. 86.
              20 Lionel Wigmore, The Japanese thrust (Canberra: Australian War Memorial, 1957), pp. 394–397.
              21 Nankai Shitai sakusen shiryô (South Seas Force operations documents).
              22 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              23 Nantô Hômen sakusen kiroku (Record of operations in the South-East Area).
              24 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              25 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              26 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              27 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              28 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              29 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              30 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              31 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              32 Lionel Wigmore, The Japanese thrust (Canberra: Australian War Memorial, 1957), pp. 394–397.
              33 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              34 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              35 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              36 Toyofuku Tetsuo, Toyofuku Shôsa kôwa (Interview with Major Toyofuku Tetsuo).
              37 Lionel Wigmore, The Japanese thrust (Canberra: Australian War Memorial, 1957), p. 403.
              38 Nankai Shitai sakusen shiryô (South Seas Force operations documents).
              39 Shima Kiyohide, Shima nisshi (Diary of Rear Admiral Shima Kiyohide).
              40 Lionel Wigmore, The Japanese thrust (Canberra: Australian War Memorial, 1957), pp. 399–410.
              41 Asashi Shinbun Shukusatsuhan (Asahi Newspaper condensed version), 25 January 1942.
              42 Toyofuku Tetsuo, Toyofuku Shôsa kôwa (Interview with Major Toyofuku Tetsuo).
              43 Daitôasen shi Minami Taiheiyô sakusen (Greater East Asian War South Pacific operations).
              44 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              45 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              46 Nantô Hômen sakusen kiroku (Record of operations in the South-East Area).
              47 Dai 5 Kôkû Sentai senji nisshi (War diary of the 5th Air Flotilla).
              48 Gunkan Tsugaru sento shôhô (Detailed battle reports of the warship Tsugaru).
              49 Nantô Hômen sakusen kiroku (Record of operations in the South-East Area).
              50 Winston Churchill, The Second World War (Melbourne: Cassell, 1948–1954), v. IV, p. 141.
              51 Louis Morton, Strategy and command: the first two years (Washington: Department of the Army, 1962).
              52 Louis Morton, Strategy and command: the first two years (Washington: Department of the Army, 1962), p. 206.

            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): 5–51.
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