Operation Downfall was the codename for the Allied plan for the invasion of Japan near the end of World War II. The proposed operation was abandoned when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki and the Soviet declaration of war. The operation had two parts: Operations Olympic and Coronet. Set to begin in November 1945, Operation Olympic was intended to capture the southern third of the southernmost main Japanese island, Kyūshū, with the recently captured island of Okinawa to be used as a staging area. Later, in the spring of 1946, Operation Coronet was the planned invasion of the Kantō Plain, near Tokyo, on the Japanese island of Honshu. Airbases on Kyūshū captured in Operation Olympic would allow land-based air support for Operation Coronet. If Downfall h