What was the codename for the planned first phase of invading Japan's home islands?

Operation Olympic was the planned first phase of the Allied invasion of Japan's home islands. It was intended to land Allied forces in southern Kyushu in November 1945.

Olympic formed part of Operation Downfall, the larger plan for forcing Japan’s surrender through invasion if diplomacy and other military pressure failed. The second phase, Operation Coronet, was planned for the Tokyo Plain on Honshu in March 1946.

Southern Kyushu was selected because it offered beaches, airfields, and positions from which Allied forces could support later operations. Japanese commanders anticipated the attack and prepared defenses throughout the region. Allied intelligence also expected Japan to mobilize military personnel and civilians for resistance.

Japan surrendered before Olympic began. The surrender was announced in August 1945, and the formal instrument was signed in September. Because Olympic was never launched, it is sometimes confused with Downfall, but the names referred to different levels of the plan: Downfall was the overall invasion concept, while Olympic was its proposed first stage.