In noble families, 족보 (Jokbo, family tree) that recorded the family tree was passed down. Essentially, the first son of the noble family would inherit this. I suppose in the olden days, it was probably an actual book, like family bible in the west. With Korean war and change in society, I am not sure that families still have some sort of old book they keep. However, the heritage, the noble class…all of that still exists today even though Korea is supposedly a democratic society with no class distinctions. All you have to say is which Gim (Kim) or Yi (Lee) you are and well, people know your family history.
That is, at least up to my generation. I grew up in Korea during the modernization so it is likely that much of this has changed now, but considering that only a few years ago, there was a startling news of “now daughters can inherit Jokbo (family tree)”, I don’t think the society has changed so much. Other than, now it is not only the sons who can inherit the family tree and Korea has finally realized that gender equality is a thing to consider. It used to be that as a daughter, you got literally crossed off (like a red x mark) from your family tree if you got married.
I know some American genealogy enthusiasts might be overjoyed by the concept of Jokbo and I do agree it is nice that you can trace your lineage far (well, if you have a certain family background). But Jokbo is not just so that you can trace your family history. The matchmakers (and yes, they still do exist at least up until a few years ago) used it to weed out certain health issues, or to make sure the match had this and that features. As a matchmaker, you wouldn’t recommend a woman for a marriage if she had too strong an astrological sign,had family history of not being able to birth a child (especially not able to birth a male child), or other issues in mental and physical health of the family. Essentially, Jokbo enabled what I would call eugenics. Feeling as though I’m a product of eugenics in my history sometimes makes me feel a little strange.