The Potsdam Declaration named four main Japanese home islands as the core of Japan's sovereignty: Honshu, Hokkaido, Kyushu, and Shikoku.
The declaration stated that Japanese sovereignty would be limited to those islands and to minor islands chosen by the Allies. This provision reflected the Allied plan to remove Japan's overseas empire and territories acquired through expansion and conquest.
The four islands are not identical in size or population. Honshu is the largest and contains Tokyo, Kyoto, and many other major cities. Hokkaido lies to the north, while Kyushu and Shikoku are southwest of Honshu. Together they form the principal geographic basis of modern Japan.
The declaration did not provide a complete final map of Japan's postwar territory. It left the status of additional small islands to Allied determination, and later occupation policy and peace agreements addressed territorial questions in more detail.