Kyushu was the target of Operation Olympic, the first phase of the planned Allied invasion of Japan.
Olympic was the opening part of Operation Downfall. Allied planners intended to land on southern Kyushu in November 1945 and seize bases for air and naval operations. These bases would then support the second phase, Operation Coronet, aimed at the Kanto Plain near Tokyo on Honshu.
Kyushu was selected because its southern position offered access from Allied bases in the Pacific and because airfields there could support later operations. Japanese planners recognized the likely target and organized defenses under Operation Ketsugo, preparing for an intense struggle over the island.
Olympic never took place. Japan surrendered in August 1945 after the atomic bombings, the Soviet declaration of war, and the invasion of Manchuria. Because the plan was canceled, its projected casualties and precise battlefield outcome remain hypothetical rather than recorded results.