The Japanese high command contained some people who wanted to push for a negotiated peace and some who still believed that there was some kind of military victory possible. For most of the war the latter dominated the command structure.

The "peace" party in the high command did have support from the Emperor, but the Emperor was not meant to actually "rule" Japan, so he lent his support behind the scenes. The main attempts to seek out a negotiated peace involved the Soviets as a neutral intermediary, because they had not declared war against Japan through the summer of 1945 (and vice versa). These "peace feelers" took two main forms: one was trying to get the Japanese ambassador in Moscow to get a meeting with the Soviets to propose that the USSR talk with the US/UK/China about giving Japan some conditions for their surrender, the other involved feeling out the Soviet ambassador in Tokyo on similar issues.

In all cases the Japanese were circumspect about what exactly they wanted. The overriding issue was always the preservation of the kokutai or Emperor system, but there were other things on their "wish list" as well, and they were willing to give some territory to the USSR in exchange for their help. But they never came out and said what they wanted, and their two approaches had little success except alerting the Allies as to the internal divisions within the Japanese leadership. The Japanese ambassador in Moscow was never allowed by the Soviets to enter into anything like formal negotiations, and the attempts to talk with the Soviet ambassador in Japan were mired with vagaries.

The Soviets had no intention of doing what the Japanese wanted, of course. They had already agreed with the other Allies that the Soviets would enter the Pacific War sometime in August 1945, and as a consequence the Soviets would be allowed to seize two important territorial possessions — the entirety of Sakhalin and the Kuril Islands. This would give the Soviets easy access to the Pacific Ocean from their eastern ports.

The Soviets told to other Allies about the Japanese overtures at the Potsdam Conference. The US and UK already knew, however, because they had cracked the Japanese diplomatic code and had been essentially reading over the shoulder of the Japanese Foreign Minister as he communicated with his ambassador in Moscow. So the fact that the Japanese were looking into negotiations was known. Different members of the Allied leadership interpreted the intelligence differently, however. Secretary of War Stimson, for example, felt that it indicated that if the Allies clarified the position of the Emperor in the postwar it might make it more likely for the Japanese to surrender in the short term. Winston Churchill also thought this. Secretary of State Byrnes, by contrast, thought they showed that the Japanese were still hardened in their resistance to the demanded unconditional surrender, and were delusional about their negotiating power. President Truman sided more with Byrnes on this, believing that a truly unconditional surrender was necessary humiliation as a result of Japan's perfidy at Pearl Harbor. As a result the Potsdam Declaration gave no real clarification as to the question of the Emperor.

All of the above is more or less straightforward historically to document; the standard source is Tsuyoshi Hasegawa's Racing the Enemy: Truman, Stalin, and the Surrender of Japan. The second question you pose is about the interpretation as to why the US dropped the atomic bombs. This is a broader and more thorny area of interpretative question. The argument that the US did it not to end the war with Japan but to induce fear in the USSR has been put forward many times over the years, most notably by the historian Gar Alperovitz. My feeling is that most historians today do not subscribe to this interpretation, though the notion that this might have been one of the many "benefits" of dropping the bomb is not completely dismissed. But generally most historians of the bomb today seem to believe that the reasons for dropping the bomb were a mixture of factors. Among the hopes that were expressed by those who were in positions to make recommendations on dropping the bomb:

• It might end the war quickly, which was valuable not only because it would put off an invasion (which was not scheduled until November, by the way), but might preclude the Soviets entering the war and getting those territorial possessions

• It would show the world how terrible these weapons were which was necessary if they were going to convince the world to not make them (Stimson in particular believed this)

• They weren't any more terrible than firebombing (some of the military people believed this)

• They would improve the US's negotiating power in the postwar (which is close to the "scare the Russians" view)

• They had to be used if they had been made — to spend that money on making fantastical new weapons and to not use them would be seen as wasteful (I don't buy this as a primary motivation but for those who made the bombs, there are elements of truth to this)

I think most historians today would see the dropping of the atomic bombs as "overdetermined" — it was a massive train of events that started years earlier, and actually dropping them as had been planned was the path of least resistance. The hard thing would have been for Truman to not want to drop the bombs, and Truman was certainly not reflective enough to think that would ever make sense. Truman himself was as far as I can tell did not really understand what the bombs would do until after they went off, and seemed shocked by the rapidity with which two of them were dropped.

On historians' views, I wrote a blog post about these awhile back if you want more information. On Truman's misunderstandings, I will be posting about this on my blog tomorrow, as it happens.

Firstly I'd like to state that it can be difficult to encompass these answers in simplistic terms like 'Japan', 'the US' and so on because (perhaps with the exception of Russia) these units are made up of number of individuals with varying opinions and thoughts. That is 'Japan' wasnt a hive mind and even among the ruling elite there were varying opinions on how the war should progress.

On the initial point there seems to have been little mention of the Emperors fate in stated Allied discussions of their intentions (primarily the Potsdam Declaration). This wasnt because they regarded him as innocent or not responsible, but most likely because they knew full well that a surrender request that included the removal and punishment of the Emperor would lengthen the war, not shorten it. I believe that originally it was considered but later on prudence declared the Emperor was best left out of the discussion.

This does not preclude the possibility that because the Emperor wasnt mentioned specifically, that the Japanese might still not have been concerned about his fate. Thus they would have been keener to surrender, a bit keener at least, if they knew for sure the Emperor would continue on. So some degree of doubt would have slowed down their enthusiasm to negotiate a surrender.

I'd agree that Japan WAS trying to surrender via Russian intermediary's prior to the bomb being dropped. This was mainly due to pressure from the Emperor who had decided the war was unwinnable. This doesnt mean it would have occurred, the pro-war faction might still have won out, but it was certainly being seriously discussed and clear movement in that direction was being seen.

So. Around June 1945 it was like this.

Most of the Japanese heirachy, including the Emperor, realised that defeat was imminent. They sought to surrender via Russian diplomatic channels. They did so with the aim of retaining as much power and influence they had, retaining the emporer and his status, losing the least amount of ground possible and forestalling any Russian invasion of nearby territory.

Russia was keen to grab as much land as they could to free up Vladivostok and to gain prestige from being involved in the defeat of Japan. Russia already knew about the The Bomb.

The Allies wanted to defeat Japan as soon as possible (#1 max priority), disarm Japan for the future and prevent the Soviets from grabbing any land or control of the situation. The US now had The Bomb and werent shy in making sure Russia became aware of it, eventually. They also knew that the Japanese and Russia were talking about Japans surrender.

I do NOT agree that the US dropped the bomb purely to 'scare' Stalin. I do believe that, not only did they want to shorten the war asap, but that they specifically wanted to do so before Russia got any toehold in the area and that any 'scaring' would assist in the slightly dangerous situation in Europe. By the end of the War the US had already started their cold war preparations.

Japan WOULD have probably surrendered. But they wanted to surrender on their terms, its not certain that given the Allied terms that they would still have surrendered. They could still have continued. For a while at least. The 'Emperor Issue' wasnt on the cards as such, but doubt about long term intentions about him may still have coloured the Japanese decision.

So he's a bit more right than you, I think. A lot of this is interpretations of intentions, stated or unstated, and there are lots of 'whatifs' that could have radically altered things.

Overall though the US dropped the bomb to shorten the war, but also to hasten its ending before the Soviets got too involved. They DID think it would make Stalin cautious but that was just a bonus.