During the Yalta Conference of 1945 , Soviet leader Joseph Stalin pledged to enter the fight against the Empire of Japan " in two or three months after Germany has surrendered and the war in Europe is terminated . " This would create another strategic front against Japan necessary to end the war . As a result of their participation the Soviets would be awarded South Sakhalin and the Kuril Islands among other concessions . The United States would aid the Soviet Army in Project Hula in preparation for the invasion
Yalta Conference
Yalta Conference
Invasion of South Sakhalin