What was the planned Allied invasion of Japan’s home islands called in 1945?

The planned Allied invasion of Japan’s home islands in 1945 was called Operation Downfall.

Downfall was the proposed full-scale invasion plan prepared by the United States and British Empire near the end of World War II. It was divided into two major stages: Operation Olympic, aimed at southern Kyushu, and Operation Coronet, aimed at the Kanto Plain near Tokyo.

Olympic was scheduled for November 1945, while Coronet was planned for spring 1946. Allied planners expected the operation to require enormous naval, air, and ground forces, and casualty estimates varied widely.

The invasion was canceled after Japan accepted the Allied surrender terms. The atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the Soviet invasion of Manchuria all shaped the final crisis that preceded Japan’s surrender. Operation Olympic and Operation Coronet were therefore components of Downfall, not alternative names for the entire plan.