Japan ranks as the world’s ninth most populous nation, with a population of 126,771,660 (2001 estimate). It is also one of the most crowded, with an average population density of 336 persons per sq km (869 per sq mi). The population is distributed unevenly within the country. Densities range from very low levels in the steep mountain areas of Hokkaido and the interior of Honshu island to extraordinarily high levels in the urban areas on Japan’s larger plains. The most crowded area is central Tokyo, where overall population density is about 13,000 persons per sq km.

The Japanese people are members of the Asiatic geographic race and are closely akin to the other peoples of eastern Asia; they constitute the overwhelming majority of the population. During the Tokugawa period, there was a social division of the populace into four classes , with a peer class above and an outcast class below. With the exception of the burakumin, the descendants of the former outcast class, this social-class system has almost disappeared. The burakumin, however, are still subject to varying degrees of discrimination.