Same-surname marriage

In his interpretation of the Book of Rites, philosopher Zheng Xuan compared same-surname marriage to zoophilia, and called it blasphemous; indicating the seriousness of the Zhou dynasty's opposition to it.

Emperor Xiaowen reintroduced a law prohibiting same-surname marriage during the Northern Wei, with a usual penalty of capital punishment.

Tang dynasty law continued to treat same-surname marriage as a crime, punishable by two years of imprisonment.

During the Joseon dynasty, when Confucianism became the founding ideology of the nation, marriage between people with the same last name and ancestral family was strictly prohibited, and even marriages with relatives from the maternal blood were banned unless the parties only share a blood relative after the sixth degree (second cousins).

The prohibition of same-surname marriage was recognized as part of Korean customary law during the Japanese colonial period.

Opponents argued that it was not feasible to ban such marriage simply due to surname, since the family name system in South Korea has been developed to a point where it became difficult to confirm the kinship between people with the same last name.