TBF my experience with Japanese and American workers is that you spend a lot of time in the office, but aren't particularly productive. Hardly surprising, given there's loads of evidence that suggests a strict enforcement of leisure time, actually increases productivity.
No one works at 100% if they work 70 hours a week and check their emails during the weekend.
Or as I once put it to a boss, when he asked me why I was leaving the office at 1700 on the dot, I finish my work in 8 hours, my colleagues need 9.