The fact that Stalin demanded the northern half of Hokkaido from President Truman on August 16, 1945, and was denied is evidence of the Soviet Union’s strong interest in influencing and occupying of the main islands of Japan.

The conflict between the U.S. and the Soviet Union over the occupation of Hokkaido has been vividly described in many previous studies, such as Tsuyoshi Hasegawa, Racing the Enemy: Stalin, Truman, and the Surrender of Japan (2005), but the point of contention in those accounts has been the occupation of the Kuril Islands and the relationship of this action to Siberian internment. Generally, such works have examined the documented correspondence between the leaders of the U.S. and the Soviet Union published in Foreign Relations of the United States. In the time since the collapse of the Soviet Union, there have not been many newly published historical records. However, it has been suggested that the Soviet Union’s request for the northern half of Hokkaido was intended to extract a concession from the U.S. in the form of the occupation of all the Kuril Islands.

This underestimation of the seriousness of the Soviet demand has been put forward in the absence of studies treating the discussions that took place within the Soviet Union before and after the demand for Hokkaido. The author has found historical documents in the Foreign Policy Archives of the Russian Federation that shed light on these issues.

These new documents show, first, that the Soviet military hoped to occupy the entirety of Hokkaido, but this was reduced within the Kremlin to the northern half. Furthermore, even after Truman’s rejection of the demand, the Soviet military continued to consider occupying the island. In addition, there were other areas besides Hokkaido within the realm of Soviet ambition. Specifically, the Soviets showed strong interest in the management of the Tsushima Straits, the Tsugaru Straits, and the Soya Straits. In connection with the Tsushima Straits, Soviet military officers and diplomats also included in their memorandums of understanding entering Pusan, Jeju Island, and Tsushima Island. Stalin’s request for the northern half of Hokkaido also appears to have been part of a strait security initiative.

To the best of our knowledge, the series of historical documents utilized in this article have not formed a part of any published research hitherto. Improved knowledge of Soviet plans for the partition and occupation of Japan should also provide additional insight into the territorial origins of the Japan that emerged into the postwar period.