The Second World War's largest theater stretched across oceans and continents
The Pacific War pitted Japan against the Allies across East and Southeast Asia, two oceans and Oceania. It folded in the war in China and the brief Soviet–Japanese War, and it staged some of the biggest naval battles ever fought.
Fighting between Japan and China dated to 1937, and to the seizure of Manchuria in 1931, but most accounts start the Pacific War in 1941, when America and Britain were drawn in. Japan had entered French Indochina in 1940 and controlled all of it by July 1941. On 7–8 December it struck Pearl Harbor and hit the Philippines, Guam, Wake, Malaya, Singapore and Hong Kong. Within six months, allied with Thailand, it also held Borneo, the Dutch East Indies, Burma, the Solomons and parts of New Guinea.
The tide turned in 1942. Carrier fleets clashed in the Coral Sea in May, forcing back an invasion force bound for Port Moresby, and in June Japan lost at Midway, after which it struggled to replace ships and aircraft as American output kept climbing. Allied offensives began that August on Guadalcanal and New Guinea; Operation Cartwheel neutralised the stronghold of Rabaul by early 1944, and the Philippine Sea and Leyte Gulf battles left Japan unable to fight surface actions, so it turned to kamikaze attacks.
Elsewhere, Operation Ichi-Go brought Japan big gains in China during 1944, while its push from Burma into India was reversed by July and Burma was freed in May 1945. The Allies had put Germany first; after its surrender they massed for an invasion of Japan that never came. An atomic bomb on Hiroshima on 6 August 1945, a second on Nagasaki three days later and a Soviet assault on Manchuria that same day led to surrender on 15 August and a signed instrument on 2 September.
Names reveal politics. Japan's cabinet chose Greater East Asia War on 10 December 1941, framing it as Asian liberation from the West; occupation authorities banned the term, and Pacific War became official. The Soviet Union, bound by a neutrality pact from April 1941, joined only in August 1945, while Mexico's 201st Fighter Squadron and Free French warships also took part.
Source: Pacific War
