The Potsdam Declaration named four main Japanese islands as Japan’s future sovereign territory.
Those islands were Honshu, Hokkaido, Kyushu, and Shikoku. The declaration also allowed for sovereignty over smaller islands that the Allies would determine. This wording defined the territorial basis for postwar Japan while excluding its overseas empire and wartime conquests.
The four islands are Japan’s principal home islands. Honshu is the largest and contains Tokyo, Kyoto, and Osaka. Hokkaido lies to the north, while Kyushu and Shikoku are southwest of Honshu. Together, they formed the geographic core of the Japanese state after the empire was dismantled.
The declaration’s territorial provisions were connected to earlier Allied statements, especially the Cairo Declaration of 1943. Japan was expected to give up territories acquired through expansion, including Korea and Taiwan. The final occupation and peace arrangements involved additional decisions about outlying islands and former Japanese possessions.