I'm also no historian, but find it difficult to believe this when the firebombings on Japan did more damage than the atomic bombs. The US and Soviet Union would have leveled Japan without atomic bombs anyway. So the US history stories puts the success of the end of the war on the atom bombs, but Japan were defeated anyway, atom bombs or not.
I agree the outcome was clear. And this was a feudal system with an Emperor, and a culture of extreme adherence to culture.
As in, Kamikazis because ordered, honour in death, or killing yourself with your own sword. Not really a culture of capitulation. Most of their cities were already firebombed, as you elude to, some more than once, yet there was still no surrender.
Without surrender, a country isn't really done. Leave it be, and they'll arm and rebuild, still at war with you. Invade, and your troops die, for a standing army still existed. Japan also had colonies, islands, resources.
And of course without surrender, even if you occupy, now you have insurgents.
It's hard to view the world through the eyes of even 80 years ago.
War weary, endless soldiers lost already, an unsurrendering Japan, and a way to put an end to it...
Two history books, "Code-Name Downfall" by Allen and "Downfall" by Frank point out that the Japanese high command was horrified by the effects of the nuclear bombs, cared a great deal about the loss of life, and were highly concerned that the next target would be Tokyo.
So they chose to end it.
There's a fair amount of detail and references in those books if one wishes to dig into it.
(I say they are "history" books as opposed to "activist" books. The latter are not worth reading.)
Some material I've seen claimed that the Japanese leadership didn't know it was a nuclear bomb. The Japanese knew immediately it was nuclear bomb, because they had a nuclear bomb development program themselves.
I think the material that claims the Japanese leadership didn't know what atomic bombs were is some revisionist's attempt to paint the actions and decisions of the time in a bad light. Fortunately, the emperor referenced atomic bombs in his surrender speech so it is fairly clear.
"Furthermore, the enemy has begun to employ a new and cruel bomb, causing immense and indiscriminate destruction, the extent of which is beyond all estimation."
Japan had no idea how many bombs we had and part of the strategy of using them in quick succession was to give the perception that we hod more than we did. It seems like Tokyo was going to be the next target:
Truman had ordered a halt to atomic bombings on 10 August, upon receiving news that another bomb would be ready for use against Japan in about a week. He told his cabinet that he could not stand the thought of killing "all those kids". By 14 August, however, Truman remarked "sadly" to the British ambassador that "he now had no alternative but to order an atomic bomb dropped on Tokyo", as some of his military staff had been advocating.
Massive scale strategic bombing and nuclear weapons are not substitutable from a military strategy standpoint and everyone would have understood the implications of that. Any similarity is superficial.
The massive bombing of Japan was a grinding war of attrition that has well-understood limitations and challenges. Military leaders in Japan were perfectly capable of understanding what those campaigns couldn't do, so it came down to a willingness to accept the losses to maintain strategic optionality, which they clearly were.
Most of the limitations of strategic bombing campaigns do not apply to nuclear weapons, which is something the Japanese military leadership also understood, though the scope of capability was uncertain (which also probably helped). If the US switched to nuclear weapons instead of conventional bombing campaigns, which was the risk Japanese military leaders had to consider, it takes most of the strategic optionality off the table at which point there is little to gain by continuing.
I think there was also the shock effect of this one tiny bomb with that much power. And the Japanese didn't know that America only had those two available. They could have had thousands for all they knew.
And this is also something that could strike their leadership. You can build bunkers against conventional bombs but for nuclear that's a different ball game
