Korean clans

The Korean bongwan system was adapted from the Chinese family clan system. It is assumed to have been created around the late Silla and early Goryeo period as a result of Silla's sinicization policies. Taejo of Goryeo promoted the bongwan system to stably distribute a growing population and create a basis for tax revenue, whilst putting an end to the obsolete bone-rank system.

Numerous clans were created throughout local administrations of all sizes and statuses. Almost all Koreans, including the Yangmin and Cheonmin caste, identified with a bongwan from the early Goryeo to the Joseon period. A bongwan affiliated with a prosperous region was widely seen as a source of personal pride, while members from a lesser or impoverished bongwan often sought to escape their genealogical status. Changes in administrative divisions profoundly influenced the merging or creation of various clans.

During the mid-to-late Joseon Dynasty, poor Koreans (commoners and members of the "surname-less class") acquired surnames by purchasing the right to adopt them. Some even fabricated family trees (jokbo) to claim ancestry from prestigious clans. This phenomenon was influenced by government policies related to slaves and a desire to elevate their social status. By the time that the Joseon class system was officially abolished in 1894, nearly all Koreans had a surname.

Traditionally, a man and a woman in the same clan could not marry, so the combination of the bongwan and the family name of a husband had to differ from that of a wife. This restriction was ruled unconstitutional by the South Korean Constitutional Court in 1997. Surname and a bongwan does not change on marriage.

In South Korea, when adopting a child as a plenary adoption, the adopted child takes the family name and the bon of the dominant (patrilineal or matrilineal) side of the parent.

When adopting a child as a ordinary adoption, which does not terminate the child's relations with the birth parents, the family name and the bon of the adopted child does not change.

Under the South Korean law, a new surname and a bon may be established with the permission of the family court. This procedure is available to a naturalized Korean citizen who uses a non-Korean surname, as well as to a person whose exact lineages are unknown.

If a naturalized Korean citizen wishes to found a surname and a bon, they need to first get a permission of a family court, and found a surname in a Family Relation Registration Office. If the naturalized Korean citizen gained a permission of a family court but did not found a surname and a bon within a month of gaining a permission, an administrative fine of up to 50,000 won could be imposed.

The determination of a surname and bon for a person whose parents are unknown is left to the discretion of the family court. When the person was found in Seoul, the court generally designates it as 'Hanyang,' where in 1996 it was reported that over 90% of the children who was abandoned in 1995 in Seoul had the bon of Hanyang. If the person discovers their birth father or mother after establishing a surname and a bon, they may adopt the surname and bon of that father or mother.

Parents can change an child's family name for the child's welfare. In this case, the parents must visit a family court to request permission to change the family name.