There is a lake named Lugu Lake between the Yongning of Ninglang County in Yunnan and the Zuosuo of Yanyuan County in Sichuan, which is 27 meters high above sea level and has a circumference of about 100 lis. Surrounded by range upon range of green mountains, water in the lake is very clear with fat fish swimming in it. The lake is one of the sources of clothes and food of the Naxi people who have lived near it for generations.

The Yongning Naxis call themselves "Moso". Until today, strong matriarchy custom in marriage and family is still kept, so people call their habitation "female kingdom" or "daughters' kingdom". In typical Moso family structure before, the family only included relatives of the mother's blood lineage---the maternal grandmother and her sisters and brothers, mother and her sisters and brothers, and mother's children and mother's sister's children. The father was regarded as an outsider. Women's status is illustrious in the family life, and women with old age and high generation are considered to be head of the family, who administer producing activities, and are in charge of distributing food and clothes. She also serves as director when people offering religious sacrifice in the family. The blood lineage genealogy is counted according to the maternal lineage, and property is inherited according to maternal principle. 

Marriage system, which meets the needs of maternal lineage family, is commonly called "Azhu" marriage by people. "Azhu" means "friend" and "partner". The main character of the marriage is that men don't take wife and women don't marry. Young men and women who don't belong to the same maternal blood lineage can choose their beloved according to their own love and will. Provided that they take the fancy of each other, they present each other tokens like bracelet or girdle, and begin to live by pairs. Because they live and work separately in two families, the man go to the woman's home to visit and sleep after the night falls, and he leaves hurriedly to his mother's family early the next morning. Children born thereafter get the mother's surname and are reared by the mother's family. Men don't have any right or duty over their children. Because of this kind of marriage family doesn't have necessary connections like economy, thus the separation of the two sides is very free: If the woman refuses being visited or the man stop visiting, the "Azhu" marriage declares finished.

After the foundation of the new China, by their inner active strength, the Naxis in Yongning reformed the original backward marriage customs gradually. Now the marriage relationship is consolidated day by day, and the big unitary matrilineal family is disappearing gradually.