It began in the 1970s, when wages were relatively low and employees wanted to maximize their earnings. It continued through the boom years of the 1980s, when Japan became the world’s second-largest economy, and everyone was on the juggernaut.

And it remained after the bubble burst in the late 1990s, when companies began restructuring and employees stayed at work to try to ensure they weren’t laid off.

Still, irregular workers — who worked without benefits or job security — were brought in, making the regular workers toil even harder.

Now, no one blinks an eyelid at 12-hour-plus days.

“In a Japanese workplace, overtime work is always there. It’s almost as if it is part of scheduled working hours,” said Koji Morioka, an emeritus professor at Kansai University who is on a committee of experts advising the government on ways to combat karoshi. “It’s not forced by anyone, but workers feel it like it’s compulsory.”