Karoshi covers deaths and serious illness, mainly strokes and heart disease, caused by excessive work, and suicide caused by work-related mental illness, sometimes called karo jisatsu. The Act on Promotion of Measures to Prevent Karoshi, passed in 2014, defines it in law and requires the government to publish an annual white paper on the subject.
For workers' compensation, the Ministry of Health, Labour and Welfare uses a working-hours test. The link to work is considered strong if overtime was about 100 hours in the month before onset, or averaged about 80 hours a month over any period of two to six months before it. This is the "karoshi line" that Japanese employees, lawyers and journalists refer to. The 2019 overtime cap, which bars 100 hours or more in one month and an average above 80 over two to six months, sits just below it.
In September 2021 the criteria were revised for the first time in 20 years. Hours close to the line now combine with other factors, such as short rest between shifts, irregular hours, frequent business travel or a psychologically demanding job, so a case can be recognised without crossing the line.
What it means for a foreign employer
- Recognition opens the door to a civil claim. Workers' compensation is no-fault, but families can then sue the employer for breach of its duty to protect employee health, and awards can be large.
- Managers are at risk too. Employees exempt from overtime pay are not exempt from the karoshi criteria. Senior staff working across Asian and Western time zones can accumulate hours that nobody is recording.
- Track hours for everyone. Employers are required to keep objective records of working time, including for managers, for health purposes.
- It shapes reputations. The 2015 death of Matsuri Takahashi, a 24-year-old new employee at Dentsu who had logged more than 100 hours of overtime in a single month, became the watershed that led to the 2018 Work Style Reform. Candidates still weigh an employer's hours culture when they choose.
Sources
- Act on Promotion of Measures to Prevent Karoshi (2014).
- Ministry of Health, Labour and Welfare, recognition criteria for cerebrovascular and cardiac disease, revised and applied from 15 September 2021.
- Labour Contract Act, Article 5.
- Industrial Safety and Health Act, Article 66-8-3 (duty to keep records of working hours, in force April 2019).