I lived in Japan for a couple of years (mid 80’s so things may have changed of course!) and I also taught English in Japan. They don’t say what school he worked for, but there are schools that only teach adults, only kids, and then there is “arubeito” where you are paid large amounts to teach private lessons. If he met someone during a private lesson, maybe a girl, he may have run away with her, as this is the time when literally no one would be on the street. When I was there, there were police booths everywhere. Everyone pretty much knew everything that was going on, and there was a MAP with everyone’s name and location by the neighborhood (because house numbers are seriously messed up, 1 may be next to 500, next to 26). Most crime was stolen umbrellas and bicycles.