<P> The Pacific War, sometimes called the Asia - Pacific War, was the theater of World War II that was fought in the Pacific and Asia . It was fought over a vast area that included the Pacific Ocean and islands, the South West Pacific, South - East Asia, and in China (including the 1945 Soviet--Japanese conflict). </P> <P> The Second Sino - Japanese War between the Empire of Japan and the Republic of China had been in progress since 7 July 1937, with hostilities dating back as far as 19 September 1931 with the Japanese invasion of Manchuria . However, it is more widely accepted that the Pacific War itself began on 7 / 8 December 1941, when Japan invaded Thailand and attacked the British possessions of Malaya, Singapore, and Hong Kong as well as the United States military and naval bases in Hawaii, Wake Island, Guam and the Philippines . </P> <P> The Pacific War saw the Allies pitted against Japan, the latter briefly aided by Thailand and to a much lesser extent by the Axis allied Germany and Italy . The war culminated in the atomic bombings of Hiroshima and Nagasaki, and other large aerial bomb attacks by the Allies, accompanied by the Soviet declaration of war and invasion of Manchuria on 9 August 1945, resulting in the Japanese announcement of intent to surrender on 15 August 1945 . The formal surrender of Japan ceremony took place aboard the battleship USS Missouri in Tokyo Bay on 2 September 1945 . Japan's Shinto Emperor was forced to relinquish much of his authority and his divine status through the Shinto Directive in order to pave the way for extensive cultural and political reforms . </P> <P> In Allied countries during the war, the "Pacific War" was not usually distinguished from World War II in general, or was known simply as the War against Japan . In the United States, the term Pacific Theater was widely used, although this was a misnomer in relation to the British campaign in Burma, the war in China and other activities within the Southeast Asian Theater . </P>

When did world war 2 in the pacific end