過労死と働き方改革 — 残業規制の歴史と現状

The word "karoushi" was coined in 1970s Japan. It took root as a medical and sociological term referring to sudden deaths from cerebrovascular or cardiac disease caused by long-hours work, and by the 1980s "karoshi" had entered English as an internationally recognized term. It is the symbolic word that drew foreign attention to the peculiarity of Japan's working style.

In December 2015, Takahashi Matsuri, a 24-year-old new hire at advertising giant Dentsu, took her own life under the strain of overwork and power harassment. Her overtime in the month immediately preceding her death exceeded 105 hours, and the case was certified as a workplace accident. The press conference and real-name disclosure by her mother Yukimi moved society profoundly: Dentsu was referred to prosecution, and the company's president resigned to take responsibility. This is the turning point that propelled the 2019 enactment of the Work-Style Reform Related Laws.

The Work-Style Reform Related Laws are an omnibus bill amending eight statutes including the Labor Standards Act, the Industrial Safety and Health Act, and the Part-Time / Fixed-Term Employment Act. Enacted in June 2018 and rolled out sequentially from April 2019, the four main pillars are: (1) upper-limit regulation on overtime, (2) mandatory acquisition of 5 days of paid leave per year, (3) equal pay for equal work, and (4) creation of the High Professional system.

The reform's heart was establishing — for the first time — penalty-backed statutory limits on overtime that had previously been only effort-based guidelines via administrative notice. The principle is 45 hours per month and 360 hours per year. Even with a special clause concluded, four absolute limits cannot be exceeded: (1) within 720 hours per year, (2) less than 100 hours per month including holiday work, (3) within 80 hours average over 2-6 months, and (4) the principle of 45 hours per month may be exceeded only 6 times per year. Violations carry up to 6 months' imprisonment or a fine of up to 300,000 yen.

Under the Ministry of Health, Labour and Welfare's workplace-accident certification criteria, when overtime of approximately 100 hours in the month preceding onset, or an average exceeding 80 hours per month over the 2-6 months preceding onset, is recognized, the correlation between work and onset is deemed strong. This is the so-called "karoushi line." The overtime caps were set at less than 100 hours per month and within an 80-hour average precisely to align with this medical criterion.

From April 2019, for workers granted 10 or more days of paid leave per year, the employer must without fail designate timing and have them take at least 5 days (LSA Art. 39 para. 7). Japan's paid-leave acquisition rate had long sat around 50% — among the lowest internationally — and the aim is to forcibly improve the "cannot-rest culture" through institutional means. Violations carry a fine of up to 300,000 yen (Art. 120).

This rule prohibits unreasonable disparities in treatment — base salary, bonuses, various allowances, welfare benefits, etc. — between regular employees and non-regular employment (part-timers, casual workers, contract employees, dispatch workers). It applied to large corporations from April 2020 and to SMEs from April 2021. Supreme Court rulings in October 2020 (Osaka Medical College, Metro Commerce, etc.) set the practical judgment standards.

The High Professional system targets workers earning 1,075,000 yen or more per year and engaged in highly specialized work (financial dealers, consultants, analysts, R&D, etc.). Conditional on the worker's consent, it excludes them from regulations on working hours, breaks, holidays, and premium wages. Created in April 2019 amid criticism as a "zero-overtime-pay bill," it requires health-safeguard measures (such as 104 or more holidays per year) and a labor-management committee resolution. The number of workers actually covered nationwide is limited to roughly the low thousands.

The overtime upper-limit regulation applied in principle from 2019, but a 5-year grace period was provided for automobile-driving work (trucks, buses, taxis), the construction industry, and physicians on grounds of industry characteristics. With the period ending, application began in April 2024. Industry-specific exceptions are set: 960 hours per year for truck drivers (relaxed from the general standard), 720 hours per year for construction (same as general), and 960-1,860 hours per year for physicians (tiers A-C).

"Service zangyo" is a Japanese-coined English term for overtime worked without wages. It is a fully illegal act of neglecting payment of premium wages stipulated in LSA Art. 37, carrying up to 6 months' imprisonment or a fine of up to 300,000 yen. Employer excuses such as "voluntary overtime," "they are management," or "covered by fixed-amount overtime pay" do not hold if the actual reality is working hours under the employer's direction and command. The statute of limitations on unpaid overtime was extended from 2 to 3 years in the 2020 amendment.

OECD statistics long ranked Japan's annual working hours among the longest in developed countries; the average has fallen to the 1,600-hour range thanks to work-style reform and the rise of non-regular employment, among other factors. Even so, this remains long compared with Germany (around 1,340 hours per year) and France (around 1,500 hours per year). Germany's Working Hours Act (ArbZG) sets 8 hours per day in principle / 10 hours maximum, while France introduced a 35-hour week under the 1998 Aubry Act. Limited to regular employees, Japan still exceeds 2,000 hours, and the gap is noted as persistent.

Measures companies have undertaken in response to the reform include: (1) objective tracking of working hours via attendance management systems, (2) forced PC shutdowns and lights-out times, (3) the effort obligation (introduced in 2019) for an "interval" rule keeping 11 hours open between the end of one shift and the start of the next, (4) introduction of telework and flextime, and (5) occupational-physician interviews for long-hours workers (mandatory upon the worker's request when overtime exceeds 80 hours per month).

Although the institutional framework has progressed, in reality many challenges remain. First is the sophistication of service zangyo: a rise in "hidden overtime" where workers punch out on the attendance system and then continue working. Second is the lack of a workload review itself: if hours are restricted but work does not decrease, the burden concentrates on management. Third is the wage gap with non-regular employment: even though equal pay for equal work has been enforced, the treatment of bonuses and retirement allowances continues to be judged case-by-case in case law.