Dishu system

Dishu (Chinese: 嫡庶) was an important legal and moral system involving marriage and inheritance in ancient China.

In pre-modern eras, upper-class men in ancient China, Korea and Japan often had more than one spouse to ensure the birthing of a male heir to their assets and titles. In China, a priority system was created to rank the offsprings' entitlement to 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). In Tang Dynasty, any man who has more than one Di wives would be considered engaging illegal marriage, liable to one year of penal labor, and the woman involved would also receive a slightly less severe punishment unless she could prove being cheated into the marriage. Either case, the marriage would be annulled.^[1]

A secondary spouse was called a ceshi (側室, lit. "side household") or Shu wife (庶妻), and her son was called the Shu son (庶子). Di sons, regardless of their age, held much higher social status than the Shu sons, and the eldest Di son (嫡長子) held overriding priority over all other children of the house.^[2] An illegitimate son, born out of wedlock, was generally categorized as a Shu son, though he would have much lower status than those born to legitimate Shu wives.

Tang dynasty law in China prescribed that if a Di son died, his eldest Di son (Di grandson) should be the successor, prioritized over all other members of the family; if a Di grandson could not be found, the Di son's next full-brother (born of the same zhengshi mother) should be the successor. If no Di offspring were available, a Shu son could be considered.^[3]

During most of the imperial China, a man could not divorce or demote a zhengshi wife (以妻為妾) unless she had committed "seven misconducts for divorce" (七出).

1. Unfilial conducts (不順父母) — considered a sin as it is "immoral" (逆德)
2. Incapable of bearing sons (無子) — considered a sin as it "threatens bloodlines" (絕世)
3. Promiscuity (淫) — considered a sin as it "disrupts clan" (亂族)
4. Jealousy (妒) — considered a sin as it "disrupts family" (亂家)
5. Having severe illness (有惡疾) — considered a sin as it "hinders family rituals" (不可共粢盛)
6. Excessive gossiping (口多言) — considered a sin as it "instigates discord among relatives" (離親)
7. Theft (竊盜) — considered a sin as it is "against common good" (反義)

However, there were three conditions, known as "three exceptions" (三不去), that forbade a man from ever divorcing his wife even if she commits the above seven sins.

1. The wife has no parental family to return to after divorce (有所娶無所歸)
2. The wife has served three years of filial mourning for deceased parent(s)-in-law (與更三年喪)
3. The husband was poor upon marriage but now wealthy (前貧賤後富貴)

The Tang law prescribed that a man caught demoting his zhengshi wife to ceshi without good cause would be sentenced to two years of penal labor, and the zhengshi wife's status would be restored.^[4] Any man who divorced his wife without legitimate reasons (the above-mentioned "seven misconducts") would be subjected to eighteen months of penal labor, and a further 100 strikes of caning if he violated the wife's protection under "three exceptions".^[5]

After the Song Dynasty, the difference between social status of Di and Shu wives/sons decreased.

References

1. 《Tang Code》：“諸有妻更娶妻者，徒一年；女家減一等。若欺妄而娶者，徒一年半；女家不坐。各離之。”
2. Du, Fangqin; Zheng, Xinrong (2005). Women's Studies in China: Mapping the Social, Economic and Policy Changes in Chinese Women's Lives. Ewha Womans University Press. p. 39. ISBN 978-89-7300-636-6.
3. 《Tang Code》：“无嫡子及有罪疾，立嫡孙； 无嫡孙，以次立嫡子同母弟；无母弟，立庶子；无庶子，立嫡孙同母弟；无母弟，立庶孙。曾、玄以下准此。 ”
4. 《Tang Code》：“诸以妻为妾，徒二年。各还正之。”
5. 《Tang Code》：“諸妻無七出及義絕之狀，而出之者，徒一年半；雖犯七出，有三不去，而出之者，杖一百。追還合。若犯惡疾及奸者，不用此律。”