People who can nod off in any situation may consider a move to Japan, where public napping, so long as one follows certain rules of etiquette, is basically seen as virtuous.

So reports the New York Times, which calls such napping a "subtle sign of diligence." The word for this type of nap, "inemuri," means "sleeping while present," says Brigitte Steger of Cambridge, and it sends a message to those nearby—be it in a work meeting or on the subway—that said napper has worked to exhaustion.

It is generally more common and accepted among older, white-collar workers, but it's a tricky concept in a nation that also sees a strong work ethic as virtuous.

"On a certain level, inemuri is not considered sleep at all," Steger wrote for the BBC last year. "Not only is it seen as being different from night-time sleep in bed, it is also viewed differently from taking an afternoon nap or power nap." But there are rules: It's fine, even common, to indulge in a crowded subway car or elsewhere in public—low crime rates help—provided you don't take up too much space; another expert calls stretching out "violating spatial norms." Women, meanwhile, are frowned upon if they look immodest while asleep.

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In short, in a nation where people often sleep less than six hours a night, then work long hours, inemuri has become what Steger calls "an informal feature of Japanese social life" that is not just accepted but somewhat necessary.

(The flip side of this "karoshi," which is literally killing people.)

This article originally appeared on Newser: Japan's Antidote to Overwork: 'Inemuri' Naps