Operation Olympic was the planned Operation Downfall component intended to invade Kyushu in November 1945.
Downfall was the proposed Allied invasion of Japan’s home islands. Olympic would have targeted the southern third of Kyushu, Japan’s southwestern main island, using Okinawa as a staging area. The planned invasion date was November 1945.
The second component, Operation Coronet, was scheduled for spring 1946 and would have attacked the Kantō Plain near Tokyo on Honshu. Together, the operations were expected to require enormous Allied forces and to produce heavy casualties.
Downfall was canceled after Japan surrendered. The decision followed the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war on Japan, and the Soviet invasion of Japanese-held territory in Manchuria. Operation Overlord, by contrast, was the Allied invasion of Normandy in Europe in June 1944.