I've always read that only cities were the target of both bombs that may, or may not, have played a role in ending WWII, but I've always wondered why only cities were chosen. I'm sure by the beginning of August and the known decision to invade the Home Islands that the Japanese would have had areas of significant military presence built up on Kyushu. I know at the time the effects of atomic bombs were not yet understood very well, so why didn't military planners target large troop gatherings? Wouldn't wiping out thousands of soldiers, equipment, and fortifications with one bomb been more effective than destroying cities? Obviously, by this point in the war, the Japanese wouldn't have been dumb enough to have huge, easy to bomb groups standing around, but wouldn't a nuclear bomb still been very effect on fortified areas? Why did the US command focus only on cities?