The Battle of Mutanchiang, or Battle of Mudanjiang, was a large-scale military engagement fought between the forces of the Union of Soviet Socialist Republics and the Empire of Japan from August 12 to 16, 1945, as part of the Soviet invasion of Manchuria in World War II. The rapid conclusion of the Manchurian campaign meant that this was one of the only set-piece battles that took place before the end of hostilities. During the action, elements of the Japanese Fifth Army attempted to delay the Soviet Fifth Army and First Red Banner Army long enough to allow the bulk of the Japanese forces to retreat to more defensible positions. Though casualties on both sides were heavy, the Red Army forces were able to break through the hastily organized Japanese defenses and capture the city ten days ah