For those unfamiliar with the Soviet Union's Aug'45 entry into the war against Japan: https://en.wikipedia.org/wiki/Soviet%E2%80%93Japanese_War https://en.wiki

For those unfamiliar with the Soviet Union's Aug'45 entry into the war against Japan: https://en.wikipedia.org/wiki/Soviet%E2%80%93Japanese_War https://en.wikipedia.org/wiki/Soviet%E2%80%93Japanese_War https://en.wikipedia.org/wiki/Soviet_invasion_of_Manchuria https://en.wikipedia.org/wiki/Soviet_invasion_of_Manchuria Japan had ample reason to fear the Red Army. Which, in overrunning Manchuria and surrounding areas, had just proven Japan's assessments of Stalin's resources and capabilities to be disastrously wrong. So, from the Japanese PoV - if they didn't surrender, how many weeks would it take for the Red Army to conquer the Japanese home islands? They were under no delusions about the brutality of a Soviet occupation.