What was the code name for the planned Allied invasion of Japan that was never carried out?

Operation Downfall was the code name for the planned Allied invasion of Japan.

The proposed operation had two major stages. Operation Olympic would have invaded Kyūshū in November 1945, while Operation Coronet would have attacked the Kantō Plain near Tokyo in March 1946. Together, these operations formed Downfall.

American planners expected fierce resistance, drawing on the fighting at Iwo Jima and Okinawa and Japan’s preparations for homeland defense. The plans included enormous troop commitments and projected heavy casualties, although estimates varied and remain debated by historians.

Downfall was never carried out. Japan accepted the Allied surrender terms in August 1945 after the atomic bombings of Hiroshima and Nagasaki, the Soviet entry into the war, and the emperor’s decision to end the conflict. Operation Olympic was not the overall invasion name; it was only the planned first phase. Operation Coronet was the second phase.