Which second-stage Downfall operation was planned to land on Japan’s Kanto Plain?

Operation Coronet was the planned second stage of Operation Downfall, targeting Japan’s Kanto Plain.

The Kanto Plain surrounds Tokyo on the main island of Honshu. Allied planners intended Coronet to follow Operation Olympic, the proposed invasion of southern Kyushu. The target period was spring 1946, after Olympic forces had secured bases and positions in southern Japan.

Coronet was never launched. Japan surrendered in August 1945, before the planned invasion timetable began. As a result, maps, troop plans, and casualty estimates for the operation describe a proposal rather than an actual battle.

The names can be confusing because Downfall referred to the overall invasion plan, while Olympic and Coronet were its two major components. Japan had its own defensive plan, Operation Ketsugō, which anticipated an Allied attack on the home islands. The surrender made all of these invasion plans unnecessary and shifted the focus to occupation and disarmament.