Karoshi: Understanding the Overwork Death Phenomenon in Japan and Beyond


Karoshi, or death from overwork, is a tragic phenomenon that has claimed the lives of hundreds of Japanese workers every year. It occurs when long working hours and excessive stress lead to sudden death. But at what point does the risk of karoshi increase significantly? And is this issue unique to Japan? In this article, we will explore the concept of the “karoshi line” and examine the global landscape of overwork.


What is the Karoshi Line?

The karoshi line is a guideline that indicates the number of working hours at which the risk of death from overwork increases. According to research by Japan’s Ministry of Health, Labour and Welfare, the risk of karoshi rises significantly when monthly overtime exceeds approximately 80 hours. This means that in addition to the standard 160 working hours per month (based on an 8-hour workday and a 5-day workweek), an employee works an additional 80 hours of overtime.

Moreover, prolonged periods of long working hours can further increase the risk of karoshi. Studies have shown that when monthly overtime surpasses 45 hours for two to six consecutive months or more, the risk of karoshi becomes particularly high.

However, it is important to note that these figures are merely guidelines, and individual differences play a significant role. Neglecting one’s health or continuing to work under stressful conditions can lead to karoshi even with shorter working hours.

Is Karoshi Only a Japanese Problem? The Global Overwork Landscape

Karoshi is not limited to Japan. As globalization advances, long working hours have become commonplace in many countries, and the issue of death from overwork has gained attention worldwide.

In South Korea, for example, long working hours are so prevalent that the country is referred to as an “overwork society.” Karoshi has become a significant social issue there. In 2018, the South Korean government amended labor laws to reduce the maximum weekly working hours from 68 to 52. However, further efforts are necessary to prevent karoshi effectively.

In China, the grueling work culture known as “996” – working from 9 am to 9 pm, six days a week – has come under scrutiny. Jack Ma, the founder of Alibaba Group, faced criticism for stating that “996 is a blessing.”

On the other hand, in Western countries, there is a stronger emphasis on work-life balance, and regulations on long working hours are more advanced. In France, for example, the “right to disconnect” law was introduced in 2017, stipulating that companies cannot require employees to respond to emails outside of working hours.

Karoshi Prevention Measures and Challenges in Japan

Japan has been taking steps to prevent karoshi. In 2014, the Act on Promotion of Preventive Measures against Karoshi and Other Overwork-Related Health Disorders was enacted, requiring the government, local authorities, and companies to implement measures to prevent karoshi.

In 2019, the Work Style Reform Legislation came into effect, introducing upper limits on overtime hours and creating the Highly Skilled Professional System (HSPS). The HSPS exempts certain high-level professionals from working hour regulations. However, critics argue that it may increase the risk of karoshi.

The challenges in preventing karoshi in Japan lie in reforming the corporate culture that values long working hours and changing workers’ attitudes. While promoting work style reforms, it is crucial to improve productivity and achieve results within limited working hours. Simultaneously, each worker must pay attention to their health management and avoid excessive overwork.


Karoshi is not just a Japanese issue but a global one, and efforts to prevent it are necessary worldwide. Understanding the karoshi line and recognizing the risks associated with long working hours are the first steps in preventing karoshi.

Companies must thoroughly manage working hours and create a comfortable work environment. At the same time, each worker must reassess their work style and prioritize work-life balance.

To create a society where everyone can work healthily and happily, each of us must raise our awareness and take action.