The Bougainville campaign was one of the largest fought by Australian forces in the Second World War. More than 30,000 Australians served on the island, and over 500 were killed in a slow, slogging campaign.
By 1945, the Australian army had been marginalised from the key battles that would defeat Japan, relegated instead to “mopping up” operations in Australia’s Mandated Territory of New Guinea and Bougainville, and on Borneo (see Wartime Issue 73). The necessity for conducting aggressive campaigns was debated at the time in the Australian Parliament and press. Although controversial, offensive action on Bougainville was justifiable. It fulfilled the Australian government’s long-stated policies of maintaining an active military effort and employing Australian forces in Australian territory. The campaign was conceived when the war was expected to continue until at least 1946. Crucially, the Australians also mistakenly believed they outnumbered the Japanese of the Seventeenth Army, estimated by the Allies as numbering up to 13,400. In fact some 40,000 Japanese army and navy personnel occupied Bougainville and the surrounding islands. Tens of thousands of Japanese died on Bougainville in military operations, but mainly from sickness, disease and starvation.