What was the name of the planned second phase of Operation Downfall, the 1946 invasion of Japan?

Operation Coronet was the planned second phase of Operation Downfall, the proposed 1946 invasion of Japan.

Operation Downfall consisted of two planned stages. Operation Olympic was scheduled first, targeting Kyushu in November 1945. Operation Coronet was planned for March 1946 and would have attacked Honshu, Japan’s largest island, with the main objective near Tokyo.

The plans were never carried out because Japan surrendered in August 1945 and formally signed the surrender document in September. Allied planners expected extremely heavy casualties if an invasion became necessary, although estimates varied widely and remain debated by historians.

Coronet was not a battle and did not occur. Its name is sometimes confused with Operation Olympic, the earlier Kyushu phase, or with Downfall, the overall invasion plan. The planned operations illustrate how uncertain the war’s outcome appeared before Japan’s surrender.