Discussing multi-ethnicity in Japan first requires knowledge of the legal and cultural foundations of Japanese identity (see "Identity Formation" and "Ethnic Diversity and the Origins of the Japanese"). Before the end of World War II, Taiwanese and Korean colonial subjects were treated as Japanese citizens and could immigrate to Japan to attend school or seek work. In 1947, however, the Alien Registration Law reclassified both groups as aliens, and the Nationality Law (1955), which defined Japanese citizenship on the basis of descent, denied citizenship even to Chinese and Koreans born in Japan. Naturalization was possible, but the long and difficult procedures discouraged many from applying.
Japan's ethnic diversity is not readily apparent. Official statistics on non-Japanese residents of Japan in 2003 represent the total number of foreigners who remained in Japan for over ninety days and were therefore required to register with local authorities, so these figures include temporary as well as permanent residents. Those enumerated represented slightly over 1.5 percent of the Japanese population.
Although the Ainu, the hisabetsu buraku (discriminated communities, also called burakumin), and Okinawans are all Japanese citizens, they are distinguished from other Japanese as minorities. The Japanese government does not collect statistics on the size of these groups, but there are a number of estimates. A study published in 1999 estimated that approximately 25,000 residents of Hokkaido identified themselves as Ainu; unofficial estimates of the burakumin population range from one to five million people or approximately 0.7 to 1.4 percent of the population. The population of Okinawa Prefecture in 2000 was slightly over 1.31 million.
Taken together, these figures suggest that approximately 4 percent of Japan's population falls outside the mainstream of persons who are accepted as culturally and legally Japanese. Is it worthwhile to discuss such a small minority? The scholars who have focused on these groups argue that their significance extends beyond their quantitative representation. Discrimination against Japan's own ethnic minorities persists, and international bodies are continuing to press the Japanese government on its minority policies. From the late 1980s, the number of foreign immigrants has actually grown: women from the Philippines and other Southeast Asian regions entered Japan to work in the entertainment industry, while other Asian women entered because of their marriages with Japanese men. Meanwhile, many Chinese from the People's Republic of China entered on student visas but sought remunerative work and overstayed their visas. Peruvians and Brazilians of Japanese descent also came to work in factory and construction jobs. The expanded presence of foreigners in Japan became a noteworthy phenomenon which was much discussed in the Japanese media. Scrutiny of the issue of multi-ethnicity provides a good opportunity to explore contemporary issues of Japanese identity.
The Ainu who inhabit Hokkaido are often called the "indigenous people" of Japan, and they were among the prehistoric groups that first settled the Japanese islands. Although they were hunters and fishers, the Ainu enjoyed extensive cultural and trading relations with the peoples residing in the Kurile Islands, Sakhalin, and even northeast Asia from early times. Attempts by the Japanese to "civilize" the Ainu began in the early nineteenth century and intensified after 1868, when Ainu lands were appropriated for Japanese agricultural settlement. A Protection Act (1899) first tried to transform the Ainu into farmers. During the twentieth century, Ainu were marginalized as a primitive and dying race that should be assimilated. By the 1950s, many Japanese believed that Ainu culture had disappeared as a living ethnic community.