Korean Diaspora
Additionally, Korean law legally defines the term Overseas Korean as referring to Republic of Korea nationals who reside overseas as well as Koreans with a Foreign Nationality. The latter group is composed of former Korean nationals who gave up Korean nationality (but barring those who did so to deliberately evade military service, at least until age 36) and children and grandchildren of former Korean nationals. It is important to note that not every descendant of a Korean can be counted as an Overseas Korean or Korean with a Foreign Nationality under this law. For example, a 25 year old man who was born a Korean national overseas but whose birth was unreported will have no documentation to prove his status as a former Korean national, and can only gain status as an Overseas Korean if one of his parents or grandparents gave up Korean nationality. Also, those who fall under Article 7 of the Addenda (Special Cases of Acquisition of Nationality for Persons of Maternal Line By Adoption of Jus Sanguinis to Both Lines of Parents) but failed to acquire Korean nationality are not able to gain the status of an Overseas Korean unless the mother or a maternal grandparent has lost Korean nationality.
Koreans in Japan who have South Korean nationality and Special Permanent Residence in Japan do not have a Resident registration number and cannot apply for a new passport from a South Korean embassy while outside Japan.
Read more about this topic: South Korean Nationality Law