I agree in principle but have always wondered if a purely military target could have been chosen, at least for the first demonstration. Something like a militar

I agree in principle but have always wondered if a purely military target could have been chosen, at least for the first demonstration. Something like a military port or base. After that it could have been made clear that arms manufacturing centers may be targeted next, followed by political centers. (They did not know we had only two bombs and would need time to make more.) As far as I know the reasoning was that the Japanese public would have to see it, but I wonder if a suitable military target on the mainland could have been found that would have minimized civilian casualties while being impossible for the regime to hide.