Clans
As with most other Korean family names, there are many Kim clans, known in Korean as bon-gwan (본관, 本貫), each of which consists of individual Kim families. Most Kims belong to one of a few very large clans. Even within each clan, people in different families are not related to each other. These distinctions are important, since Korean law used to prohibit intermarriage in the same clan, no matter how remote the relationship; now, however, only those in a relationship of second cousins or closer are prohibited from marrying.
As with other Korean family names, the Kim clans are distinguished by the place from which they claim to originate. A very large number of distinct Kim clans exist, besides those listed here. The 2000 South Korean census listed 348 extant Kim lineages.
Read more about this topic: Kim (Korean Name)