I think the Soviet declaration of war was a major factor; but more from a diplomatic than a military standpoint. The Japanese weren’t completely in denial - they realized the war wasn’t going well even if they weren’t prepared to say so out loud. So diplomatic efforts were being made to end the war on the best possible terms. Japan and the Soviet Union were not at war at this point, so the Soviets were an obvious choice to act as a neutral third party to pass along diplomatic messages. The Japanese were undoubtedly pleased that the signs were looking good; it appeared that there was a realistic chance to negotiate reasonably acceptable terms.
But what was really happening was that the Soviets were stringing the Japanese along. The Soviets wanted Japan to stay in the war for a few more months until they could get their own troops in place. They wanted to make sure they had a chance to join in the end of the war and get a share of the victory spoils. They did not want Japan to surrender to the US before the Soviets had a chance to declare war.
So the United States and other allied powers would publically say that they had no intention of offering terms. Then the Soviets would hint to Japan that, while the US was saying one thing out loud, it was whispering other things under the table. As is usually the case, it was easy to convince Japan that what they wanted to hear was true. But the reality was that the American private stance was the same as the public stance - unconditional surrender.
So the Soviet declaration of war was a shock to Japan because they suddenly realized that the country they thought was helping them end the war was just playing them for time. And they realized that there had never been a real chance of negotiating terms.
I have to object to this portion of your statement:
They didn’t have an atomic/nuclear program, how much would they know. Agree enough for not a garage but let say. “Oh my god, what if USA converted one of their hundreds of bomb factories to making these things?”
Most of Japanese military structure was flabbergasted by the speed with which USA cranked out ships, planes and bombs already. They could definitely entertain the idea that we could produce hundreds of these bombs over next few months and may not have attacked with only 2 in the stockpile.
(Yes, they had warnings of our manufacturing pestilential before Pearl Harbor and that it was a bad idea to drag USA into war and they decided it was worth it to blow up carrier fleet.)
Why? I’ve never heard of the Japanese having an atomic weapons program. If the US had tons of the other bombs, why would they assume it only had a few of the new ones?
Consider the contrast of one bomb levelling a city.
Yes, I know that’s when the instrument of surrender was delivered; however, the Cabinet meeting at which P.M. Suzuki announced he had decided to sue for peace was on August 9, the day Nagasaki was destroyed.
I would also (not in repsonse to you, Scruloose) suggest that it’s just not reasonable to conlcude either that
A) Japan considered the fire bombing to be just as bad as the A-bomb, or that
B) Japan could possibly have known that the United States did not have more bombs.
Again, the Bomb was specifically mentioned in the concession speech; the decision to surrender was made the day Nagasaki was blown up. It’s crazy to suggest that the atomic bomb wasn’t one of THE factors that caused the surrender when it did. As bad as fire bombings were, the atomic bomb was an astounding shock to Japan and, indeed, the rest of the world. Hell, Americans wrote Truman to protest its use.
As to Japan knowing whether or not the USA would have more bombs, there’s just no way that’s possible. The Japanese did, early on, have an A-bomb project but it went nowhere; they really had no way of knowing if the USA had 2 bombs or 20.
Both Germany and Japan had nuclear weapons programs, but none of them (obviously) were on hte scale of the US’s. A German U-boat was supposed to be carrying a load of nuclear materials to Japan, when Germany surrendered. The U-boat captain chose to sail directly to a US port rather than continue to Japan (which, in theory, he could have) and surrender there.
The US, itself, didn’t know for certain until July 16th of 1945 that they’d actually figured out how to build a nuke, and the US had more bombs in the pipeline than Fat Man and Little Boy, but it would have been at least a month or more after Nagasaki was bombed before they could have been used.
Another thing to consider is what would have happened if Germany and Japan had gotten nukes first. Odds are, that they would have used them at every opportunity, so it seems reasonable to me, that Japan assumed that the US would do so as well, once they’d been dropped, and probably pushed a few folks over into the “surrender” column as well.
There is speculation that one of the reasons that the answer to this question (and many others) was not brought out into public was the necessity of obscuring the role of the emperor in war decisions in order to create the fiction that he was less involved than was actually the case. This was done to allow the American ocupation to coop the emperor.
Not particularly authorative, but here you go Federation of American Scientists - I don’t think it’s a stretch to say that they would have had insight into the logistical difficulties of mass-producing these weapons.
Sorry, I guess I wasn’t clear enough. It was certainly ONE of the causes of the surrender, just like every other weapon or strategic operation in play at the time. However I don’t think it had the impact to end the war on its own, and I think the war would have ended without it to a similar timescale. Also, I’m not so convinced by the surrender speech because lets face it, which is more likely to come from a highly militarised society devoted to the concept of ‘face’ and honour?
[ul]
[li]The enemy has a devastating new weapon which cannot be fought and could destroy the world unless we surrender against our wishes[/li][li]The enemy is much stronger than us and is kicking our ass in every single way conceivable. We haven’t a hope so we’re quitting before the country is pulverized.[/li][/ul]
It’s more of a GD than a GQ question, but I don’t think the bomb did more than accelerate things by a few weeks or maybe months. Japan was going to fold no matter what, and soon.
Also, while googling Operation Starvation I came across this article. I have no idea if the source is trustworthy, but it seems to imply that by the end the air force was starting to turn to secondary targets because all the big cities had been hit, and some were ‘preserved’ to be hit with nukes. That part sounds pretty fanciful, but it also describes the general military situation at the time.