HARA-KIRI is a uniquely Japanese form of suicide. Its corporate equivalent is karoshi, “death by overwork”. Since this was legally recognised as a cause of death in the 1980s, the number of cases submitted to the government for the designation has soared; so has the number of court cases that result when the government refuses an application. In 1988 only about 4% of applications were successful. By 2005 that share had risen to 40%. If a death is judged karoshi, surviving family members may receive compensation of around $20,000 a year from the government and sometimes up to $1m from the company in damages. For deaths not designated karoshi the family gets next to nothing.

Now a recent court ruling has put companies under pressure to change their ways. On November 30th the Nagoya District Court accepted Hiroko Uchino's claim that her husband, Kenichi, a third-generation Toyota employee, was a victim of karoshi when he died in 2002 at the age of 30. He collapsed at 4am at work, having put in more than 80 hours of overtime each month for six months before his death. “The moment when I am happiest is when I can sleep,” Mr Uchino told his wife the week of his death. He left two children, aged one and three.

As a manager of quality control, Mr Uchino was constantly training workers, attending meetings and writing reports when not on the production line. Toyota treated almost all that time as voluntary and unpaid. So did the Toyota Labour Standards Inspection Office, part of the labour ministry. But the court ruled that the long hours were an integral part of his job. On December 14th the government decided not to appeal against the verdict.

The ruling is important because it may increase the pressure on companies to treat “free overtime” (work that an employee is obliged to perform but not paid for) as paid work. That would send shockwaves through corporate Japan, where long, long hours are the norm.

Official figures say that the Japanese work about 1,780 hours a year, slightly less than Americans (1,800 hours a year), though more than Germans (1,440). But the statistics are misleading because they do not count “free overtime”. Other tallies show that one in three men aged 30 to 40 works over 60 hours a week. Half say they get no overtime. Factory workers arrive early and stay late, without pay. Training at weekends may be uncompensated.

During the past 20 years of economic doldrums, many companies have replaced full-time workers with part-time ones. Regular staff who remain benefit from lifetime employment but feel obliged to work extra hours lest their positions be made temporary. Cultural factors reinforce these trends. Hard work is respected as the cornerstone of Japan's post-war economic miracle. The value of self-sacrifice puts the benefit of the group above that of the individual.

Toyota, which is challenging GM as the world's largest carmaker, is often praised for the efficiency and flexibility of its workforce. Ms Uchino has a different view. “It is because so many people work free overtime that Toyota reaps profits,” she says. “I hope some of those profits can be brought back to help the employees and their families. That would make Toyota a true global leader.” The company is promising to prevent karoshi in future.