South West Pacific theatre of World War II

The Philippines, New Zealand, the Netherlands (in the Dutch East Indies), United Kingdom, and other Allied nations also contributed forces.

Initially, US war plans called for a counteroffensive across the Central Pacific, but this was disrupted by the loss of battleships at Pearl Harbor.

The U.S. General Douglas MacArthur had been in command of the American forces in the Philippines in what was to become the South West Pacific theatre, but was then part of a larger theatre that encompassed the South West Pacific, the Southeast Asian mainland (including Indochina and Malaya) and the North of Australia, under the short lived American-British-Dutch-Australian Command (ABDACOM).

The forces remaining in South-East Asia under Japanese attack reverted to their local commanders, and were soon mostly destroyed or evacuated.

The Nanpo gun was responsible for Imperial Japanese Army (IJA) ground and air units in Southeast Asia and the South Pacific.

Australian troops at Milne Bay, New Guinea . The Australian army was the first to inflict defeat on the Imperial Japanese Army during World War II at the Battle of Milne Bay of August–September 1942.
Australian cruiser Canberra (center left) protects three Allied transport ships (background and center right) unloading troops and supplies at Tulagi .
Japanese troops load onto a warship in preparation for a Tokyo Express run sometime in 1942.
A U.S. A-20G bomber of the 3rd Attack Group bombs a Japanese merchant ship off New Guinea during the Battle of the Bismarck Sea , March 1943.
Gen. Douglas MacArthur wades ashore during initial landings at Leyte , Philippine Islands, 20 October 1944.
U.S.-manned Alligators transport Australian troops during the Battle of Balikpapan , Borneo, 1 July 1945.