[hutzlibu]

How about exploding the bomb in the sky, visible from the emperors palace and the whole city?

Or using it against an actual military target.

The message would have been clear, we can annihilate you if we want and you don't surrender. But they choose to go against the civilian population simply, because they wanted the data, of what a bomb does to a city. And that by that time bombing civilians was already pretty normalized anyway, so trying to save civilian life simply was not an issue.

[refurb]

I mean, the Allies literally bombed a major city with the first atomic weapon and Japan was like "yeah, not going to surrender". Then after the 2nd bomb, it still took days and a Soviet invasion to get them to surrender.

I'm not sure a demonstration would mean much if destroying a entire city didn't convince them.

[discardedrefuse]

The article I posted covers this (the section called Scale). When put into context, the destruction of Hiroshima just wasn't that impressive. We had already leveled 66 Japanese cities with conventional bombs. Hiroshima may have been a technical / scientific feat, but the end result paled in comparison to what we had already done before.