Since the Han Dynasty, technically, Chinese men could have only one wife. However throughout the thousands of years of Chinese history, it was common for rich Chinese men to have a wife and various concubines. Polygyny is a by-product of the tradition of emphasis on procreation and the continuity of the father's family name. Before the establishment of the People's Republic of China, it was lawful to have a wife and multiple concubines within Chinese marriage. Emperors, government officials and rich merchants had up to hundreds of concubines after marrying their first wives. In Confucianism, the ability of a man to manage a family, which usually meant more than one wife and set of children, was emphasised as part of the steps of learning for personal growth in Daxue (Great Learning). The Chinese culture of Confucianism and thus the practice of polygyny spread from China to the areas that are now Korea and Japan. Before the establishment of the modern democratic mode, Eastern countries permitted a similar practice of polygyny.
Situation in Greater China Region
After the fall of Imperial China, polygamy was banned. However, it is not unusual for a married man to take a mistress, who later becomes his next wife.
In Mongolia, there has been discussion about legalising polygamy to reduce the imbalance of the male and female population.
In Hong Kong, polygamy was banned in October 1971. However, it is still practised in Hong Kong and Macau. One example of this is Stanley Ho. Another is Lim Por Yen . Some Hong Kong businessmen have concubines across the border in mainland China.
Man-Lun Ng, M.D.of Humboldt University of Berlin reported the situation in Hong Kong: it was estimated that out of the approximately two million married couples in Hong Kong, about three hundred thousand husbands had mistresses in China (1996). In 1995, 40% of extramarital affairs involved an enduring long-term relationship with a stable partner. International Herald Tribune Kevin Murphy had reported the cross-border polygyny phenomenon in Hong Kong in 1995.
The traditional attitude toward mistresses is reflected in the saying: "wife is not as good as concubine, concubine is not as good as prostitute, prostitute is not as good as secret affair..."
The number of women becoming the secret second wife is ever increasing in Greater China region. The terms er nai/ yi nai & er nai cun / yi nai tsuen refer to the second woman and the act of having the second woman respectively. Mansions and villages are now nicknamed 'village of second woman' when a number of secret second wives live.