"Japan surrendered because they were afraid of Russia" I didn't make that claim. But the USSR at the end of WWII was a force to reckon with anyway. They were c

"Japan surrendered because they were afraid of Russia" I didn't make that claim. But the USSR at the end of WWII was a force to reckon with anyway. They were certainly able to invade Sakhalin (and they indeed took the southern half of it) and destroy Japanese armies on the mainland. I don't know enough about contemporary Soviet naval ability in order to judge if they were able to "island hop" from Sakhalin to Hokkaido and Hokkaido to Honshu. The stretches of water between the islands aren't very challenging in summer, but Hokkaido was very undeveloped at that time, so it is possible that lack of roads would stop the advance more efficiently than the sea.