Rebels and recruitment

Of the township's 110 households, more than 20 have husbands from areas outside Gansu, including nearby provinces such as Shaanxi and Sichuan.

"Some of them came here and got married before the founding of the People's Republic of China because they wanted to escape being recruited to the Nationalist army," Liang said.

Li, from the Kangxian Federation of Literary and Art Circles, said the tradition may be linked with the area's isolated location and the defeat of the Taiping Rebellion (1850-64) during the Qing Dynasty (1644-1911), one of the biggest peasant uprisings in Chinese history.

Kangxian, which sits on the border with Sichuan and Shaanxi, is located deep in the mountains. Farming can be laborious work in the prevailing conditions, so an influx of men was necessary to ensure the survival of local families, according to Li.

Some locals believe the tradition has its roots in the defeat of a number of Taiping soldiers in neighboring Sichuan.

To escape being caught and executed by the ruling dynasty, some of the survivors escaped and hid in the isolated region. To maintain a low profile, many decided to marry and take their wives' names.

According to Li, the tradition was at its height before the PRC was founded in 1949, but societal changes mean it is becoming less dominant.

"Up until the late 1970s, women enjoyed an indisputably dominant role in the family," he said. "During family banquets they always sat in prominent positions, and if a marriage failed, they took the major share of the property."

In recent years, China's urbanization program has seen huge numbers of young people move to big cities, so the old tradition is not as strong as before.

"In the past, grooms took their wife's family name on their wedding day, but in recent years it has become voluntary, so men can retain their own names, as long as both families are happy for them to do so," Li said.

Han Yangmin, a professor and expert in folk customs at Northwest University in Xi'an, capital of Shaanxi, said the belief that men are superior to women is weak in Kangxian, and it is accepted that they will live with their wife's family after marriage.

"Many parents who only have daughters or whose daughters do not want to leave are happy to find a son-in-law who will live with them," he said. "In such families, husbands and their parents-in-law usually get along very well."

The custom is also prevalent in a few relatively isolated areas in Northwest and Southwest China, such as the provinces of Shaanxi and Yunnan, he added.

"For example, in parts of Shaanxi, poor men who could not afford a dowry live with their wives and become members of the families. The man looks after his parents-in-law and inherits their property, and his children take their mother's family name."

In ancient times, a man who lived in his wife's home usually had a lower position in the family hierarchy, but societal development has seen customs evolving, and men and women are becoming equal in many places, he said.