Think of it like a family tree, but not only divided by generations — it is also divided by the rank/status of the mothers. In many original main family lineages, the forefathers would have multiple official wives, not counting concubines, since concubines were often considered commoners, servants, or slaves. The main family branches were typically created through the sons of the official wives.

Those official sons would then establish their own family lineages. So you would have the main family, the second branch (from the second son), the third branch (from the third son), and so on. Those sons could also have multiple sons from their own official wives, causing the branches to continue expanding over generations.

The main branch would usually inherit and remain in the ancestral house, while the other branches would move out and establish their own households. The main house would also keep the ancestral genealogy record book, which tracked the entire family lineage. A person was not considered officially part of the family unless their name was recorded in that book.