Inemuri

　Inemuri is the Japanese practice of sleeping on the public places. Particularly, we often sleep as we're riding a train. According to an article that I read today, there are three reason for inemuri.

　The first one is the physical characteristics of Japanese people. Since Japanese intestinum is relatively long, it takes a long time to digest foods. During the digesting, blood is concentrated in intestinum and is hard to reach head, resulting, we become sleepy. Furthermore, it is said that swaying of a train is effective in inducing sleep.

　The second one is the nature characteristics of Japanese people. Japanese people tend to concentrate on their job or study, so their fatigue level is regularly high and their brain try to rest intentionally when they're not working and studying. This is why Japanese people sleep on a train as a conditioned reflex.

　The last one is a public order of Japan. For foreigners, sleeping on the train might seem to be dangerous, but most Japanese don't think so at all. Instead, Japanese men often fear false accusation of molesters.