Would Japan have surrendered if the bomb hadn't been dropped?

Answer 1

first answer:

Absolutely, they knew they had no chance of winning by late 1944 and would eventually be forced to surrender. However it would have taken at least another year of fighting by conventional means to force the surrender. The Japanese high command actually had a plan to keep the war going until at least 1955 before the finally surrendered to a US that was by then so tired of war that we might even give Japan back territory in China and the Pacific that we had taken from them just to get Japan to agree to surrender!

second answer:

I think it is important to remember that in August 1945, both prior to & after the use of the A-Bombs it was never clear to all involved that Japan would surrender. All knew that Japan was defeated, but the Japanese Army wanted to continue fighting to the bitter end. What made the difference was the intervention of Emperor Hirohito into the discussion. Although only a figurehead, he clearly told the government leaders to surrender before the A-Bombs. It was the usage of the A-Bombs that motivated the Emperor to insist much more forcibly that unconditional surrender be accepted.

After the first two A-Bombs were dropped on Japan in early August 1945, another A-Bomb would become available in September & thereafter at least one per month. Since the invasion of Kyushu Island was not scheduled until no-earlier than November, then it is possible that the US B-29's could have dropped 3 more A-Bombs before the first phase of the invasion. If one had been used on Tokyo, then it is possible that the Emperor could have been killed, plus the top leaders of the government. That could have made surrender more difficult as centralized control may have collapsed. There was also several more months time before the main invasion would land on the main island of Honshu, thereby allowing time to drop another 3-4 A-Bombs. By this time, mass starvation on the Japanese Home Islands would be taking place separate from the A-Bombs, and massive conventional & fire bombing of other Japanese cities. However all this destruction & impending doom may not have moved Japanese Army leaders to surrender. As the senior leadership of the Army is destroyed then it would require the junior leaders to make the correct decisions. Actual events proved that Junior Army leaders were fanatically dedicated to the idea of national suicide instead of a "disgraceful" surrender.

In summary, it was the A-Bombs that allowed the Emperor's voice to be heard. If the Emperor had been arrested or killed by the Japanese Army (a real possibility) then the war would have gone on into 1946, leading to the destruction of Japan & possibly no formal national surrender. Likewise the Emperor could have been killed by Allied bombs, leading to the same result.

If the A-Bombs had not been used, then for the Emperor to come forward to insist on surrender would have required that Japan suffer some similar severe Catastrophic event(s), such as starvation, mass fire-bombing, invasion, etc.