World War II had campaigns occurring in Asia and the Pacific Ocean.
World War II . The Empire of Japan aimed to dominate Asia and the Pacific and was already at war with the Republic of China in 1937 , but the world war is generally said to have begun on 1 September 1939 with the invasion of Poland by Nazi Germany and subsequent declarations of war on Germany by France and the United Kingdom . During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma , while the Allies crippled the Japanese Navy and captured key Western Pacific islands .