Comment by wredcoll

That's a famous myth. Among other things, russia didn't have a navy, or a strategic bombing force, so they essentially posed no threat to the actual island of japan.

You are correct in the sense that Japan was going to surrender at some point, whether that was due to conventional bombings, starvation from naval blockades or an actual invasion by the USA, there's no scenario where they don't sign an unconditional surrender.

Most of those scenarios would have killed more people than the two nuclear weapons being dropped.