The Australian naval base of Rabaul, on the island of New Britain, was attacked by Japan on 23 February 1942. Rabaul became a major supply base for Japanese operations in the Pacific and one of the most heavily defended positions in the theatre.
In early 1943, Australian and American forces on New Guinea threw back the Japanese invaders and seized their base at Buna. In February, the Americans defeated the Japanese defenders on Guadalcanal, their first major victory in the Solomon Islands. The Allies were now firmly on the offensive in the Pacific and Rabaul was a tempting prize.
By now the Allies had seen sufficient evidence of the tenacity of Japanese defence to recognise that a direct assault on the heavily fortified base would result in unacceptable casualties. A new plan was devised that aimed at isolating the base instead and neutralising it through the use of airpower.
Operation Cartwheel called for a two-pronged advance through New Guinea and the Solomon Islands, resulting in the encirclement of Rabaul. The advance through New Guinea was led by Douglas MacArthur and the Solomon operations by Admiral William Halsey.
MacArthur’s forces successfully pushed north along the New Guinea coast to Lae, which fell in September. Meanwhile, Halsey’s forces secured New Georgia in August, Bougainville in December 1943, and landed at Arawe, on the southern coast of New Britain, in mid-December.
This pincer movement resulted in the encirclement of Rabaul, granting the Allies airfields from which to attack the base, and cutting it off from supplies and reinforcement.
Allied air attacks on Rabaul began in late 1943 from airbases on Bougainville. As the scale of the Allied assaults increased, so did the Japanese response from Rabaul. Hundreds of Japanese fighters were lost at the hands of the Allied escorts, while the Allied bombers pounded the facilities at Rabaul. In February 1944, Japan withdrew its remaining fighter defence, leaving the base reliant on anti-aircraft artillery.
Air attacks on Rabaul continued until the end of the war. The defence of the base had cost Japan valuable experienced airmen. Its loss left them powerless to mount any further challenge against the Allies in the South Pacific.