What was the Allied operation planned to invade Kyushu if Japan continued fighting in 1945?

Operation Olympic was the Allied operation planned to invade Kyushu if Japan continued fighting in 1945.

Olympic formed the first stage of Operation Downfall, the broader plan for invading the Japanese home islands. It was scheduled to begin on November 1, 1945, with landings on Kyushu, Japan’s southernmost main island. The operation was intended to establish bases and weaken Japanese defenses before a second invasion, Operation Coronet, aimed at Honshu near Tokyo in March 1946.

The plans were never carried out because Japan accepted the Potsdam Declaration in August and formally surrendered on September 2. Allied leaders expected an invasion to be extremely costly, and Japanese preparations for defending the home islands were extensive. The atomic bombings and Soviet entry into the war helped change the strategic situation before Olympic could begin.

Operation Olympic is often confused with Operation Coronet, which was the planned invasion of Honshu. Both were components of Downfall, while Operation Manhattan referred to the American atomic-bomb project rather than an invasion plan.