Just about anything you want to know about 'August Storm' on.......

www-cgsc.army.mil/carl/resources/csi/glantz3/glantz3.asp

Sometimes the link fails to respond, so try hitting up 'Leavenworth Papers No. 7' by David Glantz.

it's worth a look.

Japanese operations through out the Pacific were minimal, especially against the Americans, their strong points were left to wither away [the Russians would take care of the Japanese in Manchuria and China] so American casualties would be very low, that was originally the U.S's main concern.

Historian and former American Naval officer Martin Sherwin said the war most probably have ended in July if the Americans agreed to the retention of the Emperor.
"The choice in the summer of 1945 was not between a conventional invasion or a nuclear war. It was a choice between various forms of diplomacy and warfare."
The sticking point was'unconditional surrender'

If the guarantee of the Emperor was given, the war would have been over, [it was given later any way]

Just imagine if that guarantee was given earlier, no bombs dropped, no Russian attack in Manchuria, no Communist North Korea, meaning no Korean war, and the saving of hundreds of thousands of lives.

Plus some Japanese sources have stated that the atomic bombings themselves weren't the principal reason for capitulation. Instead, they contend, it was not the American atomic attacks on August 6 and August 9, but the swift and devastating Soviet victories on the mainland in the week following Stalin's August 8 declaration of war that forced Hirohito's message of surrender on August 15, 1945 [without a Guarantee for the Emperor]. Certainly the fact of both enemies weighed into the decision, but it was more the fear of Soviet occupation that hastened Japan's acceptance of defeat.