Reddit reviews The War: An Intimate History, 1941-1945

I'm going to link you to a book by Geofrey Ward - an actual, you know, historian - with supporting interviews, images, and documentation.

The Soviets invading Manchuria a thousand miles away was of course a factor in the their final decision to surrender.

Saying it was a bigger factor than their emperor(and all of Tokyo) being blown up by a nuclear bomb is patently ridiculous.