Foreign-born Japanese

A is a Japanese person of foreign descent or heritage, who was born outside Japan and later acquired Japanese citizenship. This category encompasses persons of both Japanese and non-Japanese descent. The former subcategory is considered because of intricacies of national and international laws regarding the citizenship of newborn persons.
Legal issues.
By Japanese law, adults generally cannot hold both foreign citizenship and Japanese citizenship (i.e. dual nationality is not recognized): 
Many who naturalize as Japanese also adopt a Japanese name, since names must be chosen from a list of approved kanji. Chinese or Koreans with kanji-character names may or may not have problems in this regard.
No law forbids a foreign-born Japanese to be elected as a member of Diet; Marutei Tsurunen (born Martti Turunen in Finland) is Japan's first European foreign-born member of the Diet. Theoretically, therefore, a foreign-born Japanese can become the Prime Minister of Japan.
Probably because of the difficulty in gaining citizenship and because of cultural difference, foreign-born Japanese people account for a very small percentage of the population in Japan. Many who were born and live in Japan permanently, particularly Korean and Chinese, do not naturalize. There has been a constant discussion among the government and lawmakers whether to expand their rights of permanent residence to include provisions such as the right to vote in elections, etc. Few statistics are kept on how many Chinese and Koreans have naturalized, as such statistics are not maintained by the Japanese government. Once such a person naturalizes, they are, for all intents and purposes under the law, Japanese.
The Japanese jus sanguinis policy contrasts with other countries, such as in Canada and the United States where people born natively (under jus solis) acquire citizenship on birth.