Guarding the palace sand can be said to be an ancient practice. Guarding the palace is actually a gecko. In ancient times, it was called guarding the palace. It was fed with cinnabar from a young age until it was fed with 7 kg of cinnabar, and its whole body was already red. At this time, mash it and point it on your arm. In ancient times, this method was used to test the purity of women. At the same time, it is also used to prove whether women keep their virginity.

No matter from novels or film and television dramas, we can know that the general palace sand is usually placed on the forearm, and the skin in this position is especially white and delicate, which is in sharp contrast with the red palace sand.

Pay attention to the purity of children's blood in the patriarchal society;

In the patriarchal society, the emphasis on women's chastity is mainly due to the requirement for the purity of children's blood, because it is related to the inheritance of family property and the holiness of ancestor worship. Engels, when talking about the reasons for the formation of the monogamous family, said: "It is based on the husband's rule, and its obvious purpose is to have children with unquestionable biological fathers. It is necessary to determine this biological father because children will inherit their father's property as biological heirs in the future. "

Therefore, "in order to ensure the chastity of the wife, so as to ensure that the children are born from a certain father, the wife falls under the absolute power of the husband." Even if she is killed, it is just exercising his rights. "