What are you supposed to do with your backpack on a crowded train in Japan?

Japanese spend a lot of time thinking about manners, and spend a lot of time riding trains too. So that means, of course, that people in Japan also…

What are you supposed to do with your backpack on a crowded train in Japan?
Japanese spend a lot of time thinking about manners, and spend a lot of time riding trains too. So that means, of course, that people in Japan also…