By August 1945, Japan has, for all intents and purpose, lost the war. Its armies were surrendering (or committing 'sepuku') in all the fields of battle in the Pacific and China. American bombers were dropping s__-loads of bombs of all types on the Japanese mainland, leveling cities and killing thousands. In one fire bomb attack on Tokyo in March '45, almost 100K non-combatants died. Russia has started moving troops into Manchuria/Korea. There was simply no way Japan could mount a counter-attack. Why drop the a-bombs ?