As Stalin had promised, the Soviet Union declared war against Japan on 8 August 1945, exactly three months after the capitulation of Germany, and began an offensive against Japanese forces in Northeast Asia the next day. Although an armistice halted combat between the other Allies and Japan on 15 August 1945 (14 August on the other side of the International Date Line in Cold Bay) and Japan formally surrendered to the Allies aboard the battleship in Tokyo Bay on 2 September 1945, Soviet offensive operations continued until 5 September 1945, by which time Soviet forces had overrun the Japanese puppet state of Manchukuo in Manchuria, the northern half of Korea, the Japanese province of Karafuto on the southern half of Sakhalin Island, and the Kuril Islands. Despite the Soviet Unions now-overt participation in the war, Project Hula remained secret and subject to strict censorship.