"The Japanese had expected a Soviet offensive into Manchuria but believed that it could not begin before autumn. The August 9 assault not only surprised them, but also caught them in the process of reorganizing their defenses and units. The result was massive victory by the Soviets, despite fierce and dedicated resistance by many Japanese units."
January 1, 1970
https://en.wikiquote.org/wiki/Soviet_invasion_of_Manchuria