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Battle of the Bismark Sea

Friday 9 February, 2018

Pilot Flight Lieutenant Torchy Uren of No. 30 Squadron RAAF takes a drink from his water canteen while in the cockpit of his Beaufighter during the battle


In December 1942 a decision was made by Japanese Imperial Headquarters to reinforce its position in the South West Pacific by moving 6,900 of its New Guinea troops from Rabaul to Lae. Despite the level of risk involved due to the known strength of the Allied air power in the region, the alternative – a long march of 230 km through the mountain and jungle terrain of New Guinea – was thought to be a far worse option.

On 28 February 1943 a convoy consisting of eight destroyers and eight troop transports, with an escort of approximately 100 fighters, set out from Simpson Harbour in Rabaul.

In the meantime the Allies had detected that preparations for the Japanese convoy were underway and naval codebreakers in Melbourne and Washington DC had decrypted and translated messages indicating the intended destination and date of arrival. A Japanese float plane, used in advance of convoys, was sighted on 7 February 1943 and Lieutenant General George Kenney, the Allied Air Forces South West Pacific Area Commander, ordered an increase in reconnaissance patrols over Rabaul. Intelligence was conveyed to General Douglas MacArthur on 25 February.

Japanese ship movements (black) and Allied air attacks (red) during the battle.


New and more innovative techniques had also been developed by the Allied Air Forces with the aim of improving their chances of successful air attacks on ships. Clear weather conditions also enabled them to detect and shadow the convoy and a sustained air attack on 2 – 3 March 1943 followed. Further attacks by Patrol Torpedo boats and aircraft followed on 4 March.

In what became known as the Battle of the Bismark Sea most of the Japanese task force was destroyed – all eight transports and four of the destroyers were sunk. Japanese troop losses were heavy – out of 6,900 troops, only about 1,200 made it to Lae and another 2,700 were rescued from barges and rafts by destroyers and submarines and returned to Rabaul.

The battle was never mentioned in Japanese media but it was reported two weeks later that Tokyo had announced that in future all Japanese soldiers were to be taught to swim.

No further attempts were made by the Japanese to reinforce Lae by ship nor were there any further attempts to prevent Allied offensives in New Guinea.

Allied aircraft execute a low-level attack on a Japanese ship


Japanese ship, Kenbu Maru, under attack


The battle was seen as a disaster for the Japanese and a master-class in air power by the Allies. This was a lopsided naval defeat with not a single ship involved on the victorious side. In the words of one of the destroyer skippers, Captain Tameichi Hara, ‘Never was there such a debacle” and Vice Admiral Gunichi Mikawa, Commander of the Japanese Eighth Fleet at Rabaul, “It is certain that the success obtained by the American air force in this battle dealt a fatal blow to the South Pacific.”  In contrast, General Douglas MacArthur called the Allied victory “one of the most complete and annihilating combats of all time”.

The battle clearly demonstrated to the Japanese that they could not operate convoys in areas within range of land-based Allied aircraft. As aerial attacks continued to be a major problem for Japanese ships in the area, they were forced to rely on smaller coastal vessels, barges and submarines to provide a lifeline to their vital strategic outposts in the archipelago. 

In what has been described as Australia’s most important victory in World War II, any possibility that Australia might be invaded had been eliminated. Without the necessary supplies or reinforcements, the Japanese shifted to a much more defensive strategy and would never regain the initiative for the rest of the war.


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