What was the codename for the planned Allied invasion of the Japanese home islands in 1945?

Operation Downfall was the codename for the planned Allied invasion of the Japanese home islands in 1945.

The plan had two main stages. Operation Olympic was intended to invade southern Kyushu, while Operation Coronet was planned for the Kanto Plain near Tokyo. Olympic was projected for November 1945, and Coronet was tentatively scheduled for March 1946.

The planned invasion was never carried out because Japan surrendered before the operations began. Allied planners expected fierce resistance and prepared for very large troop commitments, especially for the assault on Kyushu and the later advance toward Tokyo.

Operation Downfall is sometimes confused with Operation Overlord, the codename for the Allied invasion of Normandy in 1944. The Japanese surrender ended the need for Downfall, although occupation forces still entered Japan and began demobilizing its military.