[Barrie Yates]

A Russian invasion of Hokkaido could not possibly have taken place in the timescale you suggest Eric. The Russian invasion of Manchuria was a purely land based conflict - Russia did not have the naval transports available for a sea borne attack on Japan and an airborne attack cannot succeed alone. Russia declared war on Japan at that time in order to share in the spoils of war. McArthur stopped that idea.
As for the nuclear weapons being a waste of money - there are still people around - a few allied ex-prisoners who would have died if the war had not been terminated as quickly as it was - they would give you a very good explanation of what it meant to them - and yes, I had family members who were captured by the Japanese and some of those died.