What was the proposed Allied invasion plan for the Japanese home islands in 1945 called?

Operation Downfall was the proposed Allied invasion plan for the Japanese home islands in 1945.

The plan had two major stages. Operation Olympic was scheduled for November 1945 and would have invaded southern Kyūshū, Japan’s southernmost main island. Operation Coronet was planned for spring 1946 and would have attacked the Kantō Plain near Tokyo on Honshū.

Allied planners expected the operation to require enormous forces and estimated very high casualties, although forecasts varied considerably. Japan prepared its own defense plan, Operation Ketsugō, to resist an invasion of the home islands. Downfall was never carried out because Japan surrendered in August 1945.

The plan is sometimes confused with Operation Overlord, the Allied invasion of Normandy in June 1944. Overlord concerned the liberation of Western Europe, while Downfall concerned a possible invasion of Japan. The cancellation of Downfall avoided the planned amphibious campaign and the battles that would have followed.