12. Kyushu was to be Japan’s main point of defense
The planning for Operation Downfall was that Kyushu was to be a preliminary operation, establishing a staging area for the main invasion of Japan in Honshu. Fourteen divisions were assigned to Operation Olympic, tasked with landing on the beaches, driving inland and capturing intact the port facilities, and securing airfields. They were then to develop a defensive perimeter after capturing about one-third of the island. By contrast, twenty-three divisions were assigned to the invasion of Honshu in Operation Coronet, where the main defense of the home islands was expected. American planners believed they would find Kyushu relatively lightly defended, with much stiffer resistance expected on Honshu.
In fact, beginning in the spring of 1945, the Japanese began reinforcing Kyushu, planning on making the battle where the main focus of their defense of the home islands. Well aware that victory was impossible, the Japanese hoped to inflict severe casualties in a protracted campaign which would lead to a negotiated peace. Troops were recalled from Manchuria and Korea, and others were transferred from Honshu. By late summer 1945 there were fourteen divisions deployed in Kyushu, and another nearly two million armed civilians, trained by Japanese troops in methods of killing unsuspecting Americans. Japan’s troops were not all fully equipped for combat in 1945, but an arms buildup was underway.