On 6 August 1945 the United States exploded an atomic bomb over Hiroshima and revealed to the world in one blinding flash the start of the atomic age. As the meaning of this explosion and the nature of the force unleashed became apparent, a chorus of voices rose in protest against the decision that opened the Pandora’s box of atomic warfare. The decision to use the atomic bomb was made by President Truman. There was never any doubt of that and despite the rising tide of criticism Mr. Truman took full responsibility for his action. Only recently succeeded to the Presidency after the death of Roosevelt and beset by a multitude of problems of enormous significance for the postwar world, Mr.
Truman leaned heavily on the advice of his senior and most trusted advisers on the question of the bomb. But the final decision was his and his alone.  The justification for using the atomic bomb was that it ended the war, or at least ended it sooner and thereby saved countless American-and Japanese-lives. But had it? Had not Japan been defeated and was she not already on the verge of surrender? What circumstances, it was asked, justified the fateful decision that “blasted the web of history and, like the discovery of fire, severed past from present”?  Thefirst authoritative explanation of how and why it was decided to use the bomb came in February 1947 from Henry L. Stimson, wartime Secretary of War and the man who more than any other was responsible for advising the President in this matter.  This explana- On August 6, 1945, at precisely 8:16 a.m.
, thefirst atomic bomb exploded in Hiroshima, Japan, just seconds after leaving the Enola Gay.It carried with it the equivalent of 20,000 tons of TNT.Everything within four square miles was desolated. On August 9, 1945, the second atomic bomb exploded at approximately 11:01 a.m. in Nagasaki, Japan, after being dropped from the B-29 Bockscar.This bomb contained the equivalent.