What was the first phase of the planned Allied invasion of Japan called in 1945?

The first phase of the planned Allied invasion of Japan was called Operation Olympic.

Operation Olympic was the proposed invasion of Kyushu, Japan’s southernmost main island. It was scheduled for November 1945 and formed the first stage of Operation Downfall, the broader plan for invading and occupying Japan. The second stage, Operation Coronet, was planned for the Kanto Plain near Tokyo in March 1946.

The invasion plans were never carried out because Japan surrendered in August 1945. Allied planners expected fierce resistance based on battles such as Iwo Jima and Okinawa, and Japanese authorities were preparing civilian and military defenses. The projected casualties and the uncertain duration of an invasion were major issues in wartime planning.

Operation Olympic is often confused with Operation Downfall, which was the overall invasion plan, or Operation Coronet, which was its proposed second phase. The atomic bombings of Hiroshima and Nagasaki, the Soviet attack on Japanese forces in Manchuria, and Japan’s internal surrender decision made the planned invasion unnecessary.