On December 7??, 1941, Japanese forces carried out surprise attacks on Pearl Harbor, attacks on British forces in Malaya, Singapore, and Hong Kong and declared war, bringing the US and the UK into World War II in the Pacific.

After the Soviet invasion of Manchuria and the atomic bombings of Hiroshima and Nagasaki in 1945, Japan agreed to an unconditional surrender on August 15. The war cost Japan and the rest of the Greater East Asia Co-Prosperity Sphere millions of lives and left much of the nation's industry and infrastructure destroyed.