Dishu system

Dishu (Chinese: 嫡庶) was an important legal and moral system involving marriage and inheritance in the Chinese cultural sphere. In pre-modern eras, upper-class men in China, Japan, Korea, and Vietnam often had more than one spouse to ensure the birth of a male heir to their assets and titles. In China, a priority system was created to rank the offsprings' entitlement to this inheritance. Under this system, a man was allowed one official wife, called a zhengshi (正室, pronounced seishitsu in Japanese, lit. "formal household") or di wife (嫡妻), and her son was called the di son (嫡子). A woman would have to go through a formal wedding to become the di wife, otherwise she would be considered a concubine of her husband. A man could only have one di wife unless he had already divorced another. In the Tang dynasty, any man who had more than one di wife would be considered to be bigamous and would be liable to one year of penal labor. The woman involved would also receive a slightly less severe punishment unless she could prove she had been cheated into the marriage. In either case, the marriage would be annulled. A secondary spouse was called a ceshi (側室, lit. "side household") or shu wife (庶妻). A man might participate in a small ritual, or no ceremony, to take on a shu wife. Several shu wives were allowed for one man at the same time according to the law. A shu wife‘s son was called the shu son (庶子). Shu sons had to regard the Di wife of their father as their mother and respect her. Their birth mother would be called yiniang (姨娘, lit. "aunt"). Based on social standards, the di wife's major responsibilities were managing all shu wives and taking care of them...