What was the planned second phase of the Allied invasion of Japan, targeting Honshu, called?

Operation Coronet was the planned second phase of the Allied invasion of Japan, targeting Honshu.

Coronet was intended to follow Operation Olympic, the planned invasion of Kyushu. The proposed landing area was the Kanto Plain near Tokyo, Japan’s political and industrial center. Planners scheduled the operation for March 1, 1946, after Olympic had established bases in southern Japan.

Coronet formed part of Operation Downfall, the overall invasion plan for the Japanese home islands. It would have involved a very large Allied force, including American and Commonwealth units. The expected resistance and potential casualties made the operation one of the most consequential plans under consideration in 1945.

Japan’s surrender made Coronet unnecessary. The operation is therefore known mainly through planning documents, force estimates, and later historical studies rather than battlefield reports. Confusing Coronet with Olympic reverses their intended sequence and locations.