Sleeping on the job may get you fired in the U.S., but in Japan it’s a badge of honor—a sign that an employee has worked to the point of exhaustion. Inemuri—literally “sleeping on duty”—has been practiced in Japan for at least 1,000 years. But it’s become especially common in recent years because of Japan’s grueling work culture, which demands long hours and little time away from the office. On top of that, almost half of Japanese adults sleep less than six hours a night. Employees can nod off for a few minutes to hours without raising eyebrows, but there are guidelines: Their posture must be upright throughout the power nap, an indication that they weren’t just slacking off. “You have to sit as if you are listening intently,” Brigitte Steger, a professor at Cambridge University in the U.K., told The Guardian, “and just put your head down.”