Main article: Military history of Japan during World War II
Japan was the leader of the Axis powers in the Pacific Theatre. Some people consider that World War II actually began with the invasion of China by Japan in 1937. The war ended with the capitulation of Japan after the atomic bombings of Hiroshima and Nagasaki by the US. Although the US saw most action in the Pacific Theatre, the United Kingdom also had a role in Japan's defeat, particularly in the Burma campaign. The USSR did not declare war on Japan until 9 August 1945 when it invaded Manchuria.