Last Saturday, one of my students called and cancelled her lesson because she had worked all night and was too wrecked physically to maker her lesson. This is relatively common behavior among some Japanese employees. In fact, back at my former company, I came in one Saturday morning to find that one of the salesmen had worked all Friday night.
Since these workers are salaried, they don't get paid for the overtime and, more often than not, they don't take compensation time. I've often asked them why they are required to do this. They usually tell me that it is somehow their own fault. The most common excuse is that he or she is too slow and incompetent. My student said she is essentially a perfectionist. My husband's students have said that the company is understaffed and that requires them to work a lot of overtime, but mine seem reluctant to blame the company.
I asked my student why, when things got busy, that someone else in the office didn't pick up the slack. She said that the company is organized in such a way that each person is relatively specialized and can't really accomplish the tasks of other employees. I'm not sure if this situation is particular to her company or common in all Japanese companies but I do know that such specialization was not uncommon among the Japanese staff in my former office. The strange thing was that it wasn't the case among the foreign staff. We could do almost every aspect of each other's work so that, if someone was sick or took a vacation, he or she could be covered for.
I'm not sure if this situation is by design or a byproduct of some cultural aspect which I'm not aware of but it sure allows the companies to take advantage of their employees and discourage the taking of vacation time. If you are the only one in your section who can accomplish a task, your absence for any reason not only results in that work not getting done for the duration but also ensures you will return to a huge pile of work and have to endure a lot of overtime to get caught up.