A jokbo (族譜) is a genealogy that records, generation by generation, the lineage of a family sharing a surname (seong) and clan seat (bongwan). Starting from the founding ancestor, it lays out who descended from whom, what offices they held, and whom they married — showing a family's roots and branches at a glance. In Joseon, a jokbo was more than a family record: it was also a document of status, proof that one belonged to a yangban house.
What a jokbo contains
A jokbo usually opens with a preface stating the family's history and the purpose of its compilation, followed by the founding ancestor and the origin of the clan seat. The main text arranges people by generation, recording names and courtesy names, birth and death years, offices held, spouses and their families, and the locations of graves. Traditional genealogies settled on a patrilineal format, carrying the line through sons.
Late Joseon: genealogies bought and sold
Because yangban status meant exemption from military service and social privilege, the late Joseon period burned with the desire to become yangban. When the state sold office and status through blank warrants and grain payments, commoners who had built up wealth bought them to raise their standing. On top of this, people bought up the genealogies of fallen yangban houses in whole, inserted their names into others' genealogies (a practice called tutak), or forged lineages outright. "Making up ancestors who never existed" was far from rare.
So how many are "real" yangban?
Against this backdrop, the fact that many families today hold the genealogy of a yangban house is no guarantee that their ancestors were truly yangban for generations. Through the status laundering of the late Joseon period, a great many genealogies were newly created or reworked in later times. Judging by population makeup too, nobi and commoners were the majority in Joseon, so probabilistically the ancestors of most Koreans today were likely commoners or nobi. The story that "our family were yangban" may in fact be a trace of that era's social climbing.
The test, just for fun
This site's test springs from exactly that question — "is my family register real or fake?" The idea of reading an ancestor's status from the hands and body is not science but a game borrowed from old superstition, so please take the result lightly.