What was the name of the planned Allied invasion of Japan that surrender made unnecessary?

Operation Downfall was the planned Allied invasion of Japan that surrender made unnecessary.

The operation was the proposed invasion of the Japanese home islands. It had two major stages: Operation Olympic, the planned invasion of Kyushu, and Operation Coronet, the planned invasion of Honshu near Tokyo.

Olympic was scheduled for November 1945, while Coronet was planned for March 1946. Allied planners expected fierce resistance because Japanese forces were preparing for a decisive defense of the home islands and civilians were being organized for resistance.

Japan’s surrender in August 1945 canceled the invasion plans. The cancellation avoided the enormous projected casualties that an invasion might have caused, although estimates varied and historians continue to debate how military, political, and atomic-bomb factors shaped the decision to surrender.