Which planned operation targeted the Kantō Plain near Tokyo?

Operation Coronet was the planned operation targeting the Kantō Plain near Tokyo.

Coronet was the second stage of Operation Downfall, the proposed Allied invasion of Japan. Planners expected it to follow Operation Olympic, which was intended to seize southern Kyūshū. Coronet was tentatively scheduled for March 1, 1946.

The Kantō Plain was chosen because it surrounds Tokyo and offered strategically important approaches to Japan’s political center. The proposed landings would have involved the U.S. First and Eighth Armies, with additional forces expected to follow.

Coronet was never launched. Japan’s surrender in August 1945 canceled Downfall before either invasion stage began. Coronet is sometimes confused with Downfall itself: Downfall was the overall plan, while Coronet was its proposed second operation. Olympic was the separate first stage aimed at Kyūshū.