What was the overall Allied code name for the proposed invasion of Japan in 1945–1946?

Operation Downfall was the overall Allied code name for the proposed invasion of Japan in 1945–1946.

The plan had two major parts. Operation Olympic was scheduled for November 1945 and would have attacked southern Kyūshū. Operation Coronet was planned for spring 1946 and would have invaded the Kantō Plain near Tokyo on Honshū.

Downfall was canceled after Japan surrendered. Allied planners expected the operation to require enormous forces and feared severe casualties on both sides. The proposed invasion would have followed the capture of Okinawa, which was intended to serve as a staging area and source of air support.

Operation Downfall is often confused with Olympic and Coronet because those names referred to components rather than the entire plan. It is also distinct from Operation Overlord, the Allied invasion of Normandy in June 1944.