Inemuri is a Japanese word which means "to be asleep while present." It refers to falling asleep in social gatherings, at classes, at work, and at various public functions. In the West, of course, falling asleep at an event is generally viewed as a cause for awkwardness and shame. In Japanese culture, there is a special place for inemuri, and it is actually viewed as a cause for pride, rather than embarrassment.
For many Japanese, the implication of inemuri is that someone is exhausted from working too hard, and that he or she is sacrificing sleep at night to get work done. Work is a very important part of Japanese culture, especially hard work, for both adults and youths, although for younger Japanese the work is education-related, rather than conducted in an office. In a country where people compete to log more work hours than friends and colleagues, inemuri is the ultimate indicator of hard work.
Generally, inemuri is viewed as positive and acceptable for people in high-ranking positions, but not for the lower ranks. A superior in a work environment can indulge in inemuri in front of inferiors, in other words, but inferiors would not generally fall asleep before their bosses. Students may also engage in inemuri as they study for grueling exams and attempt to advance themselves in the Japanese educational system.
While long work hours and extreme stress may not be healthy, inemuri is actually beneficial. Brief periods of sleep can rejuvenate the mind, allowing someone to focus and helping to clarify ideas. Ideally such nano naps should last at least a few minutes for their benefits to be felt, and as fans of the siesta and the power nap know, a 20-30 minute period of sleep in the middle of the day can be quite pleasant.
The concept of inemuri explains why you may occasionally see high profile Japanese figures who appear to be napping during social and public events. Typically, inemuri is a very light sleep, from which the sleeper can easily awake, allowing him or her to follow events while resting the mind. As observers of cats may be aware, inemuri has also been adopted by the feline world.