What was the U.S. code name for the planned invasion of Japan that never took place in 1945?

Operation Downfall was the U.S. code name for the planned invasion of Japan that never took place in 1945. It was the overall plan for a massive assault intended to force Japan’s surrender if the war continued.

Downfall had two major phases. Operation Olympic was scheduled to land on Kyūshū in November 1945, while Operation Coronet was planned for the Kantō Plain near Tokyo in March 1946. Allied planners expected fierce resistance and enormous casualties.

The atomic bombings of Hiroshima and Nagasaki, the Soviet entry into the war, and Japan’s internal decision to accept surrender terms made the invasion unnecessary. Planning documents nevertheless reveal how seriously Allied leaders prepared for a prolonged campaign.

Operation Overlord, by contrast, was the code name for the 1944 Allied invasion of Normandy in Europe. Olympic and Coronet were components of Downfall, not alternative names for the entire Japanese invasion plan.