Which planned Operation Downfall phase was intended to invade the Kantō Plain near Tokyo?

Operation Coronet was the planned Operation Downfall phase intended to invade the Kantō Plain near Tokyo.

Coronet was designed as the second major stage of the proposed invasion of Japan. It was scheduled for spring 1946, after Operation Olympic had captured part of southern Kyūshū and established additional bases. The planned landings would have taken place around the Kantō Plain, the broad region surrounding Tokyo and Yokohama on Honshū.

Coronet would have been followed by a drive north and inland toward Tokyo. Planning documents envisioned a very large Allied commitment, including American armies and proposed Commonwealth forces. The operation was never launched because Japan surrendered in August 1945.

The name is easy to mix up with Olympic. Olympic was the first phase and targeted Kyūshū; Coronet was the second phase and targeted the Kantō Plain. Both names belonged to Operation Downfall, the umbrella invasion plan.