Soviet forces invaded Manchuria immediately after declaring war on Japan in August 1945.
At 11 p.m. Trans-Baikal time on 8 August 1945, Soviet Foreign Minister Vyacheslav Molotov informed Japan’s ambassador that the Soviet Union considered itself at war with Japan from 9 August. Just after midnight, Soviet forces launched a large offensive against Japan’s Kwantung Army in Manchuria, then a Japanese-controlled region of northeastern China.
The invasion struck from several directions, including areas west, north, and east of Manchuria. Soviet forces also attacked Japanese positions in southern Sakhalin and the Kuril Islands during the final weeks of the war. The rapid offensive created a major strategic crisis for Japan’s leaders.
Manchuria is sometimes confused with Korea because Japanese forces occupied both areas and Soviet troops later entered northern Korea. The immediate large-scale offensive following the declaration of war, however, was the invasion of Manchuria.