On 6 August 1945, at exactly 8:15 a.m., the first atomic bomb in history was dropped on Hiroshima, Japan. Along with the Soviet entrance into the war on 8 August, the atomic bomb was one of the “twin shocks” that finally compelled Emperor Hirohito to make the decision to surrender. The real “shock” of Hiroshima, however, was not the introduction of a “new and most cruel bomb,” as Hirohito described the atomic bomb in his 15 August radio broadcast announcing the decision to surrender. Rather, it was the capability of the United States to produce the rumored .super weapon. that Japan’s own top atomic scientists had repeatedly deemed impossible, the latest instance of such denial coming only several weeks earlier on 21 July 1945—five days after the Manhattan Project’s successful Trinity atomic test at Alamogordo, New Mexico.