In one of his last diary entries, teacher Yoshio Kudo lamented workdays that started early and could last until nearly midnight. Two months later, he became a victim of karōshi — death from overwork.

Kudo's taxing schedule was far from an exception in Japan, where teachers work some of the longest hours in the world, saddled with tasks that range from cleaning and supervising school commutes to after-school clubs.

A 2018 OECD survey found Japanese junior high school teachers work 56 hours a week, versus an average 38 hours in most developed countries.