[dragoon500ly]

The final US plan for the invasion of Japan was Operation Downfall. It consisted to two components: Operation Olympic, the invasion of Kyushu, to secure naval and air bases and Operation Coronet, the invasion of the main island of Honshu.

The Joint Chiefs of Staff, in the summer of 1945, had three basic choices for Downfall. First, to encircle Japan by invading China, establish bases there and use those bases to first blockade and then to invade the home islands. Second, to isolate Japna via naval blockade and massively reinforce the existing bombing campaign and force Japan to surrender without having to invade the home islands. Third, was to assault Japn through amphibious invasion and force the Japanese to surrender by seizing Tokyo and key industrial areas.

The JCS strongly debated these courses, the naval supporting option two and the army supporting option three. The first option was rejected as it would needlessly run up casualties without forcing Japan to surrender. Other worries were that the growing war wariness would force an end to the war before final victory was achieved. There was also the very real concern that Kapanese forces outside of the home islands would continue to fight on. On May 25, 1945, the JCS issued a directive to launch an amphibious assault on Japan. General Douglas MacArthur was placed in command of Operation Olympic.

On 18 June, the JCD presented their plans to President Truman, who issued the go order for Downfall. And on July 26, he, British Prime Minister Clement Atlee and Soviet leader Josef Stalin issued the Potsdam Declaration warning Japan to surrender of face "total destruction". The Japanese rejected this ultimatum and on July 30, the JCS directed Generals MacArthur and Wedemeyer (commanding in China) and Admiral Nimitz to coordinating plans for Downfall. Operation Olympic would jump off first, followed four months alter by Coronet.

The British contribution to Olympic would consist of the British Pacific Fleet and elements of the Royal Air Force. The British would contribute more forces for Coronet. One of the factors limiting the size of the British forces were the deep concerns that Japanese units the remainder of the Far East would go on fighting, even if the home islands did surrender. It would be necessary to retain forces for posisble use. The British still planned for a force of from three to six divisions to be committed to Cornet. The specific units were never designated, but would have most likely consisted of at least one British, Australia, New Zealand, India and possibly a Canadian infantry divisions.