Japanese had a nuclear program, so they understood perfectly well what an atomic bomb was. Thay didn't know how to make one, but the concept was familiar. At that point, there were very few Japanese cities over 100 000 inhabitants that weren't more than 50% destroyed (I think there were 6-7 by that point).
Japanese government didn't even schedule an emergency meeting after Hiroshima. There wasn't a week that went by that they didn't have their cities destroyed. Atomic bombs at that time didn't really have a tactical military application, so for Japanese it was business as usual. They were perfectly willing to sacrifice their population and knew those cities would have been destroyed anyway. Whether it was one bomber in one day or 500 bombers in one day, it mattered little.
The hawks wanted to inflict huge losses on allied invaders so they get concessions, while doves wanted Soviets to mediate. With Soviet entry to war, both options were taken away. Army was positioned in the south, expecting the allies and north was lightly defended. Soviet invasion would have met little resistance. Since the Soviet Union is now an enemy, there was no hope for mediation.
