I think the material that claims the Japanese leadership didn't know what atomic bombs were is some revisionist's attempt to paint the actions and decisions of

I think the material that claims the Japanese leadership didn't know what atomic bombs were is some revisionist's attempt to paint the actions and decisions of the time in a bad light. Fortunately, the emperor referenced atomic bombs in his surrender speech so it is fairly clear. "Furthermore, the enemy has begun to employ a new and cruel bomb, causing immense and indiscriminate destruction, the extent of which is beyond all estimation." Japan had no idea how many bombs we had and part of the strategy of using them in quick succession was to give the perception that we hod more than we did. It seems like Tokyo was going to be the next target: Truman had ordered a halt to atomic bombings on 10 August, upon receiving news that another bomb would be ready for use against Japan in about a week. He told his cabinet that he could not stand the thought of killing "all those kids". By 14 August, however, Truman remarked "sadly" to the British ambassador that "he now had no alternative but to order an atomic bomb dropped on Tokyo", as some of his military staff had been advocating.