What was the Allied plan for invading Japan that was abandoned after Japan surrendered in 1945?

Operation Downfall was the Allied plan for invading Japan that was abandoned after Japan surrendered in 1945.

The proposed operation had two major stages. Operation Olympic was planned for October 1945 and would have involved landings on Kyūshū, Japan’s southernmost main island. Operation Coronet was scheduled for March 1946 and would have targeted the Kantō Plain near Tokyo on Honshu.

Downfall was expected to be an enormous and costly campaign. Allied planners prepared for fierce resistance because Japanese forces had mobilized for a homeland defense and civilians were encouraged to resist invasion. Japan’s surrender meant that neither Olympic nor Coronet was carried out.

Operation Downfall is often confused with Operation Overlord, the Allied invasion of Normandy in June 1944. Overlord liberated much of Western Europe and led to Germany’s defeat; Downfall was a later Pacific plan that never progressed to invasion. The occupation of Japan began instead on 28 August 1945.