I’ve lived in Japan—in and near Tokyo—for four decades, and on the trips I’ve made to Seoul I’ve enjoyed observing similarities and differences between the two cities. One of the differences was uniformed soldiers riding the subway in Seoul, something I’ve never seen in Tokyo. Another was what looked like emergency supplies stored on subway platforms; I’m guessing they were there in case the subways had to be used as bomb shelters. (I can’t read Korean, so I might have misidentified the items or their purpose.)

Postwar Japan has done a lot of preparation for natural disasters but has had essentially no civil defense measures against military threats. That might be changing, though. Just a couple of weeks ago, for the first time, the city of Tokyo designated 105 subway stations as emergency evacuation sites in case of missile attacks [1, in Japanese]. This was prompted not only by the continued threat from North Korea but also by what has been happening in Ukraine.

[1] https://news.yahoo.co.jp/articles/34fd48f39ee9b8a78197f350e8...

I was mostly thinking of a much more severe war cycle like WW1 or WW2 which have been out of most living people's memory at this point and so don't drive the culture as much any more. Before that it was constant bloodletting. We truly live in unprecedented times.

As a Korean I can tell you we mostly don’t care about their threats day to day. Their missiles don’t even make our news cycle sometimes. But we did care when they were more brazen (like sending specialists to assassinate our president) and now anti-communism is one of driving ideologies of our society, for better or worse. Calling someone “socialist” can be an insult :p

I didn't get that from day to day life, but you'd probably feel it in things like mandatory military service, and the fact that escalators going down to subway stations were deeper than normal.