Hi All,
I was listening to a hardcore history podcast by Dan Carlin ( I highly recommend if you have not listened before ) and he was discussing the atomic bombing of Japan at the end of the second world war. In western history the narrative is that the devastation caused by the bombings and the threat of more was a large influence in the Japanese capitulation and eventual surrender, but from my little understanding of the air campaign the Americans wages on the Japanese the atomic bombings while delivering a new level of destruction, it was certainly not a new phenomena considering the impact the firebombing had on other cities during the war.
I would love to here some opinions ( or suggestions for further reading ) on the influence the Soviet invasion had on Japanese government thinking at the time and how this ultimately played into the decision to surrender.
The influence on the Japanese Surrender by the Soviets was not the declaration of war, but rather the declaration combined with the absolute victory the Red Army had in their campaign. After the declaration of war, the Red Army swooped into Japanese controlled Manchuria (Manchukuo) with over a million men strong army. The devastating force and the superior tactics, strategy, manpower, and equipment led to a complete Japanese defeat on the mainland. It laid bare the fact that the Japanese Army was poor equipped for a land campaign, and it also opened the possibility that the Soviet's would then jump from the mainland to Northern Japan where the Japanese commanders had made no preparations.
So to bring it back together. The declaration of war was significant because it ended any hope for Soviet mediation on a conditional surrender/armistice. However, the main cause for fear in Tokyo was how strong the Red Army was, how devastatingly quick they made victory against the Kwantung Army (The army in Manchuria), and the real threat of a dual front Soviet/US attack on mainland Japan.
Now, this is where it becomes a historical debate. On the side of historians who say that the dropping of Nuclear bombs was immoral, or unnecessary for Japanese capitulation they will point to the Soviet declaration of war as the reason why such measures was not necessary for peace. The other side will say that the declaration and invasion would have little bearing to Japanese commanders, and that the complete destruction of Hiroshima and Nagasaki were enough to persuade the Emperor into declaring surrender. My view? In between. I do think the Nuclear bombs had a profound affect on the Emperor, plus the fear that the American's had over a hundred more ready to be dropped which is what was being rumored at the time (untrue, the two were all the Americans had at the time). I also think the complete destruction of the army in Manchuria proved to be a strike against the idea of a valiant defense of the mainland. It, I think, was a one-two-three punch that knocked the Japanese to Unconditional Surrender. The first being the first bomb dropping, then the Red Army rolling through Manchuria, and then the second bomb dropping. To attribute to one is to ignore the other.