11. Japan offered few suitable beaches for attack
Unlike the coast of France, where the Allies had several potential landing points and Hitler himself was convinced that the invasion would come at a place other than Normandy, Japan had few beaches where a seaborne invasion could land. The complex two-pronged plan for Operation Downfall evolved as a necessity given the opportunities offered. American planners had to consider the speed of completing the invasion in the shortest time possible given the difficulties encountered as a result of Japan’s distance from points of resupply. The planners also had to consider the casualties which they would incur, and the fighting on Okinawa and in the Philippines indicated they would be considerable.
The planners picked three main points as the targets for Operation Olympic, with 35 landing beaches, code-named after automobile manufacturers. Planners assumed that the troops going ashore would outnumber the defenders by a factor of 3:1, when in fact some areas were heavily defended and others had no defenders at all, other than coast watchers. Prior to the invasion of Kyushu, three offshore islands were to be taken, beginning in the last week of October 1945. These islands were intended to provide anchorages for vessels damaged during the assault itself and in the actions supporting the troops after the beachheads were obtained, a necessity learned during the fight for Okinawa when so many ships crowded offshore presented an array of targets for the kamikazes.