It seems that opinion and propoganda have more of a grip on this thread than anything else. Go read some history, people! And then read some more. By doing so you will get a concensus of what modern historians have discovered about what was happening.

The Soviet Union had agreed a date with the other Allies when they were going to attack the Japanese, not in the home islands, as they did not have the specialised equipment they would have needed, but in Manchuria.

The Japanese (especially the Emperor and those close to him) were starting to sue for peace. They had asked the USSR to intervene, but the Soviets had no wish to because of their agreement to come in against the Japanese in September. So they didn't say that the Japanese had contacted them.

Certainly there were plenty of Allied scientists who wanted to see if their bomb worked. But there was only enough fissionable material for the two bombs, even with some that was possibly captured off a submarine that was taking it from Japan to Germany (not substantiated this last bit, but possible/likely).

Certainly the early surrender of the Japanese did 'save Allied lives'. No one was looking forward to invading the Japanese home islands, although plenty of materiel was making its way there for that job. But, as mentioned above, tht Japanese were sueing for peace, perhaps not as vigourously as the Allies would have hoped. But the story that Truman dropped the bomb to save Allied servicemen's lives is only partly true. But it's the kind of story that you want the folks at home to believe, isn't it?

And Displaced C - WW1 conventional? You have perhaps forgotten about the poison gas used by both sides, and the bombing and shelling of civilian targets (particularly by the Germans).