? They do that in my Japanese town of Kumagaya but that is for the kids to go home because it is getting dark. It changes to 4 or 5pm depending on the time of year. Are you sure that music is to remind adults that it is time to go home?
It is for kids.
I dunno, they did it in hachioji when I lived there several years back. I remember it being at 6 and I remember my coworkers telling me that was the reason for it but I could be mistaken.
One of the customers I've worked for in Japan has alerts over the loudspeakers when it's time to go home. The company I work for had people working insane hours (14+ daily) and acted like it was normal. The people were obviously not doing much work staying later, but they wanted to appear to be dedicated. I'd much rather my people work hard when we need it and have time to unwind when we don't. I see it as a failing of management of every day requires an emergency level of effort.