What was the planned second stage of Operation Downfall against Japan?

Operation Coronet was the planned second stage of Operation Downfall against Japan.

Coronet was intended to invade the Kantō Plain on Honshu, Japan’s largest island, and to advance toward Tokyo. It was scheduled for spring 1946, after Operation Olympic had captured southern Kyushu and provided bases for further operations.

Operation Downfall therefore had two linked parts: Olympic against Kyushu and Coronet against the Tokyo region. Allied planners expected the Japanese defense of the home islands to be severe, and estimates of possible casualties varied widely.

Coronet was canceled because Japan surrendered in August 1945. The planned invasion never occurred, so later discussions about its likely casualties are estimates rather than records of an actual battle. Coronet should not be confused with Operation Ketsugō, Japan’s defensive plan for resisting the Allied invasion.