Inter-clan marriage and antithetic marriage

In Chinese society males should not marry females of the same surname (this have been largely disregarded in recent era as the Chinese population expanded to such an extent that people who hold the same surname might have little or no relation with each other at all). This is seen as incest and it is thought there is a risk that abnormal births might result. Marriage of a son to close relatives of his mother, however, is not seen as incest. Different clans might have more than one surname. Historically, there were numerous important clans living along the Yellow River in the ancient China, like the tribe of Huang Di with the common surname Ji and that of Yan Di with the surname Jiang. Because marriage to one's maternal relatives was not thought of as incest，these families sometimes intermarried from one generation to another.
Over time Chinese people became more geographically mobile. Couples were married in what is called an extra-clan marriage, or better known as antithetic marriage. This occurred in the midst of the New Stone Age, i.e. around 5000 BC. According to modern Chinese scholars of a Marxist persuasion Matriarchy prevailed in society at that time, therefore husbands needed to move to, and live with, their wives’ families. Yet individuals remained members of their biological families. When a couple died, the husband and the wife were buried separately in the respective clan’s graveyard. Offspring would be buried with their mother. Antithetic marriage still happens in modern China. In Yunnan, males and females in the minority group known as Nakhi form temporary couples, and they call each other “Ahchu” rather than “husband and wife”. The male “Ahchu”s live and work in the home of the female “Ahchu”s.