What was the Allied plan for a full-scale invasion of Japan called?

Operation Downfall was the Allied plan for a full-scale invasion of Japan. It was never carried out because Japan surrendered in August 1945 before the planned landings began.

The proposed operation had two major stages. Operation Olympic was scheduled to invade Kyushu in November 1945, while Operation Coronet was planned for the invasion of Honshu near Tokyo in March 1946. Together, these operations formed Operation Downfall.

The plan reflected Allied expectations that Japan would resist fiercely. The Battle of Okinawa had already demonstrated the potential cost of invading Japanese-held territory, and Allied planners anticipated enormous military and civilian casualties.

Japan’s surrender followed the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and internal political decisions by the Japanese leadership. Because of those events, neither Olympic nor Coronet took place.