|Bougainville Island is located at the north-west end of the chain which forms the Solomon Islands. A rugged mountain range runs the approximate 190-kilometre length of the island. The local population, which numbered around 50,000 at the start of the war, lived mainly in the flat country in the island’s south.
Bougainville became important to the Japanese forces based in Rabaul as a transit base for operations in the south-eastern Solomon Islands, at Tulagi and Guadalcanal. Ultimately, the base was to support operations in the New Hebrides and Fiji to blockade the Allied supply route from the United States to Australia. Consequently, the 6th and 18th Cruiser Squadrons, which included the light cruiser Tenryû, entered Queen Carola Harbour at Buka Island on 8 March 1942. The area was occupied in late March and early April 1942 with little resistance from elements of the Australian 1st Independent Company, which had been dispatched to the area during 1941.
The Japanese 17th Army, under Lieutenant General HYAKUTAKE, in conjunction with navy construction and garrison units, quickly set about establishing airfields and concentrating forces in four key sectors: Buka in the north, Kieta on the east coast, Mawaraka on the west coast, and around Buin and Faisi in the south. By October 1943, there were approximately 46,000 army and 20,000 navy personnel stationed in Bougainville, with sufficient supplies and ammunition for an extended campaign.
The Allied counter-offensive operations in the South-West Pacific Area developed through 1943. The recapture of the Solomons, including Bougainville, was to preclude Allied landings in New Guinea, New Britain, and eventually Rabaul. By August 1943, the decision was taken to “island hop” around Rabual, thus isolating Japanese strengths, rather than to undertake costly frontal assaults. The Japanese commander on Bougainville anticipated an Allied counter-attack on Bougainville by the end of 1943, but he did not expect it to be on the west coast of the island. On 1 November, General Vandegrift led the 3rd US Marine Division to secure a beachhead at Torokina, on the northern shore of the large arc of Empress Augusta Bay.
General HYAKUTAKE was initially reluctant to dispatch a strong counter-offensive force to Torokina, as he believed the main Allied landing was still to come, probably on the east coast. This, and the fact that the bulk of the Japanese air strength was sent back to Truk that month after heavy losses from US carrier-based planes, allowed Vandegrift to secure a substantial perimeter around the beachhead. By December, an airfield had been completed, allowing American and New Zealand fighters to raid Rabaul.
Meanwhile, the 37th and Americal Divisions, led by Major General Griswold, had arrived to protect the perimeter at Torokina. HYAKUTAKE opened the long-awaited counter-offensive on 9 March 1944 with Lieutenant General KANDA’s 6th Division and elements of the 38th Independent Mixed Brigade. The Japanese forces met with some early successes, but were weakened by fatigue and disease from the outset and were unable to counter US armoured, artillery and air strengths. By 25 March, KANDA ordered a complete withdrawal, having suffered an estimated 9,000 casualties, and losing more to malaria and dysentery during the retreat. Thereafter, the two sides were content to secure and patrol their respective perimeters and keep a watchful peace.
With MacArthur set firmly on recapturing the Philippines, command and responsibility for all areas in the Solomons and Australian New Guinea was transferred from October 1944 to the First Australian Army led by Lieutenant General Sturdee. The American units at Torokina were replaced by Lieutenant General Savige’s II Australian Corps, based on five infantry brigades. Air support for the Australians was provided by the No. 1 Group Royal New Zealand Air Force (RNZAF) and No. 84 Wing Royal Australian Air Force (RAAF). Allied control of the sea had prevented resupply to the Japanese forces on Bougainville since February 1944, resulting in around one-third of all Japanese troops being deployed in gardening duties, and another one third sick.
The Australian units under Savige were not content to maintain the perimeter established by the Americans, but set out to “destroy the Japanese on Bougainville”. Units from the 7th Australian Brigade pushed along the Numa Numa Trail, which crossed the mountains north from Torokina, in late November 1944. By early January 1945, elements of Colonel KANEKO’s 81st Japanese Regiment had been pushed off a central feature on the trail known as Pearl Ridge. For the next few months, Australian units sent patrols forward from Pearl Ridge to harass and disrupt the Japanese north–south line of communications along the east coast.
The 29th Australian Brigade, led by Brigadier Monaghan, crossed the Jaba River to the south of Torokina in mid-December to begin the advance towards the main Japanese concentration around Buin in the south of the island. The Japanese 13th Infantry Regiment initially provided limited “hit-and-run” resistance to the Australian southward push. KANDA, who had taken command of the Japanese 17th Army after HYAKUTAKE had suffered a stroke in February, planned for a concerted campaign to delay the Australian 7th Brigade, which had replaced the 29th Brigade, at Slater’s Knoll, a position on the south side of the Puriata River, about mid-way between Torokina and Buin. By early April, Japanese casualties from the failed counter-attacks by the 13th and 23rd Japanese Regiments around Slater’s Knoll numbered over 1,600. Thereafter, two battalions from the 15th Australian Brigade gradually pushed south, under almost constant, though reduced, Japanese resistance.
In the northern sector, Savige initially ordered a battalion from the 11th Brigade to advance along the coastline with the ultimate aim of destroying the Japanese forces in the Bonis Peninsula and on Buka Island. The Australians suffered heavy casualties from units of the 38th Independent Mixed Brigade who were well dug-in along Tsimba Ridge.
By mid-1945, KANDA’s Japanese forces were confined to an area around Buin in the south, and the Bonis Peninsula and Buka Island in the north. Australian forces continued to press both areas, and Japanese forces continued to resist, often sending parties through the dispersed Australian line to disrupt communications and supply in rear areas.
The Australian policy in Bougainville of seeking the destruction of an isolated, though underestimated Japanese force, received much criticism, both during the war and since. General Blamey defended his policy on the grounds that such aggressive patrolling would avoid a loss of Australian morale and was ultimately a cost effective means of freeing local peoples and reducing army resources and commitments. In any event, the Australians lost 516 killed or missing from November 1944, while the Japanese losses for the entire campaign are estimated to be 30,000 army and 12,000 navy personnel killed.
Contributed by Steven Bullard (AJRP)
Bougainville units (Jpn)
Bougainville units (Aust)
Human face of war
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