What do six parents mean?

The eight-character six parents refer to grandparents, parents, sisters, sons of wives and brothers, sons of mothers and daughters.

According to Records of Records of the Historian and Biographies of Guan Yan: "The degree of service will strengthen the six parents." Tang Zhangshou Festival justice: "Six relatives refer to grandparents one, parents two, sisters three, sons of wives and brothers four, sons of obedient mothers five and sons of daughters six." It also refers to relatives, relatives, etc.