Japan is an extremely homogeneous society with non-Japanese, mostly Koreans and Chinese, making up only about 1% of the population. The Japanese people are primarily the descendants of various peoples who migrated from Asia in prehistoric times; the dominant strain is N Asian or Mongolic, with some Malay and Indonesian admixture. One of the earliest groups, the Ainu, who still persist to some extent in Hokkaido, are physically somewhat similar to Caucasians. Japanese is the offical language. Of major concern to Japanese government policy planners are the expected steady decline in the population during the 21st cent. (the population decreased for the first time in 2005) and the large and growing portion of the population that is elderly.
Japan's principal religions are Shinto and Buddhism; most Japanese practice both faiths. While the development of Shinto was radically altered by the influence of Buddhism, which was brought from China in the 6th cent., Jodo, Shingon, Nichiren, and other Japanese varieties of Buddhism also developed. Numerous "new religions" formed after World War II and attracted many members. One of these, the Soka Gakkai, a Buddhist sect, grew rapidly in the 1950s and 60s and became a strong social and political force. Less than 1% of the population are Christians. Confucianism has deeply affected Japanese thought and was part of the generally significant influence that Chinese culture wielded on the formation of Japanese civilization (see Japanese architecture; Japanese art; Japanese literature).