It's actually not clear that the atomic bombs were what caused Japan to surrender. One must remember that the Soviet Union declared war on Japan during the same week that the bombs were dropped. I'm inclined to suspect that the Soviet entry into the war was more important--perhaps even decisive on its own. After all, Curtis LeMay's command had already conducted brutal firebombing raids on more than 60 Japanese cities. The raid on Tokyo, on March 9-10 1945, killed more civilians than died at Hiroshima. If this type of destruction did nothing to convince Japan to surrender, I'm skeptical that merely dropping a more advanced type of bomb was what did it.