What was the codename for the planned second stage of the invasion of Japan near Tokyo?

Operation Coronet was the planned second stage of the invasion of Japan near Tokyo.

Coronet was intended to follow Operation Olympic, the planned invasion of southern Kyushu. Its objective was the Kantō Plain on Honshu, the region containing Tokyo and Yokohama. The proposed landings were scheduled for March 1946 after Allied forces had secured bases and supplies through Olympic.

The plan was part of Operation Downfall, the overall Allied concept for defeating Japan through invasion if other measures failed. Military planners anticipated major fighting because the Kantō Plain was Japan’s political and industrial center and would have been defended heavily.

Coronet was never conducted. Japan’s acceptance of the Potsdam Declaration in August 1945 ended the need for the invasion plan. The operation’s name is therefore associated with contingency planning rather than an actual battle or landing.