This is a world where women are superior to men. There is not much difference in physical and mental strength between women and men, but women have longer life spans than men and have unique fertility.
Dazhou is such a country that is bound by the blood of mother. In Dazhou, a woman can have multiple husbands. People only know her mother but not her father.
Women have surnames, but men have no surnames. Only after marrying, a man can get a surname from his wife.
Men can only infer from the time of their wife's pregnancy and the appearance of the child whether the child has his own bloodline.