1, because of the lack of extensive records in history, it is still unknown. In the Song Dynasty, because the traditional prohibition of official genealogy was broken, folk genealogy compilation began to flourish. So the genealogy is also increasing.

2. The genealogy of this period consists of three parts: The first part is the genealogical chart. If you want to know whose family tree someone belongs to and who his father is, you can see it at a glance; The second part is the genealogical text, which is arranged according to the sequence of each person listed in the genealogical chart, and introduces each person's name, father taboo, line number, age, official position, title, year of death, year of death, posthumous title, marriage and so on. These conjunctions, which are more than 50 words of the old man and only two or three words short, are actually biographies. Make people know its origin, and the lineage table is therefore more complete; The third part is the appendix. It is of great value to study the origin, migration, distribution and culture of surnames.