What is Zhang's genealogy? Why does a generation have two words and a generation has three words?

China has a strong sense of family and attaches great importance to his ancestral home and family background. Therefore, both nobles and civilians have their own genealogy and genealogy books, stipulating that each generation has the same word in its name. If it is two words, so is the radical. For example, in A Dream of Red Mansions, Jia Jia has three generations of names, with the same word in the middle, namely Jia Daishan and Jia Daihua. There are two generations of names with oblique jade characters, namely Jia Zhen and Jia Lian.

There are other sayings. If the number of names in three consecutive generations is the same, it is called three generations of Qing Dynasty. If the number of names is different, three words in one generation and two words in one generation, it is called three generations of mixed names.