It was the bombs. And the final realization that not only would the USSR not mediate a soft landing, as Sato, from Moscow had been telling Togo, all along, but, as revealed at the 9-10 August rigged gozen kaigan, the Soviets would not honor the remaining neutrality period, for the year past when they had declined to renew it, as was mandated/anticipated. They had attacked. As I’ve told you before, the decision was not a reductionist one. It was both. But the plan was for what happened to have happened anyway. The Emperor, against all custom, was asked by Togo to express his desires. It was known that he would direct that the Potsdam Declaration be accepted. Before the Soviet attack or the second bomb.
More books. A pair to be read together: THE DAY MAN LOST and JAPAN’S LONGEST DAY, both by The Pacific War Research Society. Japanese folk. IMPERIAL TRAGEDY/Coffey. BEHIND JAPAN’S SURRENDER/Brooks. JAPAN’S DECISION TO SURRENDER/Butow. THE FALL OF JAPAN/Craig. Lots of stuff. Kort/THE COLUMBIA GUIDE TO HIROSHIMA AND THE BOMB has a lot of original message traffic between Sato and Togo. Other books are on the shelf. Go thou and read, a lot.
Japan’s leaders knew full well what had struck Hiroshima. Nishima, the premier nuclear physicist in Japan, who had headed one of the two Japanese atomic bomb development programs, was on the 2nd plane into Hiroshima. Nailed it as an atomic bomb. The hardliners response was how might this be countered, and a conviction that we couldn’t have any more. Followed,during the gozen kaigan, by the 2nd. Which resulted in a panic by one hardliner: they may have a hundred of them. Nice of them to think so.
The bombs obviated what the Japanese were counting on. The Soviets would have a difficult time invading the Home Islands. The US, invaders from the sea, par excellence, would not now have to get their feet wet on Kyushu, where the Japanese, far more numerous than the Americans had planned on, were waiting for them on the correct beaches. Drea/MACARTHUR’S ULTRA). Which mean that the Japanese plan to run up a staggering bloodbath (ketsugo plan) to obtain from the US a moderated form of terminating the war, was gone. There would be no invasion, by anybody. They might have a hundred of those things. They certainly had a hundred B-sans. One bomb, one plane, one city. And the two were only 4 days apart. Surrender.
It is now time to go and be a host. Enjoy your books.