Barely half the vacation days allotted to Japanese workers are ever taken, an average of nine days per individual a year.
The problem in Japan in some ways parallels the situation of American workers, many of whom don't get guaranteed paid vacations at all. But those who get them usually do take all or most of them.
Japanese must use their vacations for sick days, although a separate law guarantees two-thirds of their wages if they get seriously ill and take extended days off.
That means workers save two or three vacation days for fear of catching a cold or some other minor illness so they can stay home, said Yuu Wakebe, the health and labor ministry official overseeing such standards.
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Wakebe himself routinely does 100 hours of overtime a month, and took only five days off last year, one of them for staying home with a cold. He managed to take a vacation to Hawaii with his family.
"It is actually a worker's right to take paid vacations," he said. "But working in Japan involves quite a lot of a volunteer spirit."
Younger workers feel uncomfortable going home before their bosses do. Working overtime for free, called "sah-bee-soo zahn-gyo," or "service overtime," is prevalent.
Job descriptions also tend to be vague, especially in white-collar occupations, meaning a person not coming in translates to more work for others in his or her team.
The new law will allow for more flexible work hours, encouraging parents to spend more time with their children during summer months, for instance, when school is closed.
Although Japan is notorious for hard work, it's equally known for inefficiency and bureaucracy. Workers sit around in the name of team spirit, despite questionable performance and productivity.
Experts say the law is a start, while acknowledging the roots of the dilemma lie deep.
When night falls in Tokyo, groups of dark-suited salarymen can be seen, drinking at drab lantern-bobbing pubs under the train tracks, unwinding before heading home. They laugh, guzzle down their beers and pick at charcoal-broiled fish.
Ask any of them: they haven't taken many days off. One said the 12 days he took off last year were too many.
Regulating time off might be easier to implement if the economy improves under Prime Minister Shinzo Abe's anti-deflationary policies that weakened the yen, a plus for giant exporters such as Toyota Motor Corp.
The overwork problem intensified during the past two decades of economic stagnation in Japan. The use of cheap labor became common to stay competitive in a rapidly globalizing economy, while the culture of loyalty to the company stayed.
Abe, not a person noted for taking long vacations, has been stressing the need for change.
Japan's work ethic, he said, is "a culture that falsely beatifies long hours."