The Soviet invasion of Manchuria began on August 9, 1945, during Japan’s final days of World War II.
Soviet forces crossed into Japanese-held Manchuria shortly after midnight on August 9, launching simultaneous offensives from the east, west, and north. The operation followed the Soviet declaration of war delivered to Japan on August 8 in Moscow time.
The timing was linked to the Yalta agreement, under which the Soviet Union had promised to enter the Pacific War within three months of Germany’s defeat. The invasion began between the atomic bombing of Hiroshima on August 6 and the bombing of Nagasaki on August 9.
The date is sometimes confused with August 8 because that was when the declaration of war was delivered in Moscow. It is also distinct from August 15, when Hirohito’s surrender announcement was broadcast to the Japanese public. The Soviet offensive rapidly weakened Japan’s position in northeast Asia.