The girls who took a lifelong vow of chastity are now in their 80s, the last survivors of a unique custom

Her mother carefully undid Liang Jieyun's plaits, combed out the strands and pinned them into a bun. When her friends put up their hair, they wore the red clothing of brides. But as Liang left her girlhood behind and stepped across the family threshold, she was embarking on a lifelong commitment to remain single.

At 85, Liang is a rare survivor of a custom stretching back to the early 19th century in parts of southern Guangdong. Women here could vow to remain a "self-combed woman", or zishunü, leaving their parents' home to work without marrying. "If I hadn't become a 'self-combed woman', the landlord would have forced me into marriage," she said.

Pretty girls were often forcibly taken as wives or concubines. It happened to two of her friends, and they killed themselves.

Becoming a zishunü gave women an unusual degree of independence in a world that allowed them little education, voice or freedom. But it came at a heavy price. They toiled in factories or other people's homes to support their families. Women who broke their pledge of celibacy were supposed to kill themselves, though by Liang's era, such expectations had largely disappeared.

The words recited with the eight strokes of the comb hint at the uneven path ahead: "First comb for luck, second for longevity, third for contentment, fourth for safety. Fifth for freedom …"

Shatou village, Shunde, was once a centre of this practice. Down an alleyway, tucked behind the high modern white-tiled homes, lies a two-storey grey building with an elegant courtyard before it. In front of its gate, mulberry trees sprawl inside a red-brick wall.

The Hall of Ice and Jade – named after the saying "as pure as jade, as unsullied as ice" – was built to shelter these women in old age, although it is now a museum.

Liang is tiny – perhaps 142cm (4ft 8in) – and fine-boned. She sits on a bench, swinging feet in black galoshes, beside Huang Li-e, a 90-year-old with a mischievous smile and an aptitude for teasing. They have never had husbands, children – or second thoughts.

"No regrets," they say in unison.

"A lot of men chased after me," Liang added, with a shooing motion: "I told them to go away."

The custom was one form of "marriage resistance" in the Pearl river delta. Others included "delayed marriage": wives would not move to their husband's home or have sex with him for the first few years. It may have emerged because Shunde was a silk production centre, giving women opportunities in the factories. The area also placed a heavy emphasis on female chastity, said Ye Ziling, who has interviewed many survivors, possibly helping to ensure the women's vows were respected.

While they chose to become self-combed, even running away to do so when their parents disapproved, most came from poor households.

"Often, their families couldn't offer good dowries. Their status would be even lower than an ordinary girl's in their new family," said Ye. "They were also the eldest daughters and might already be the main labourer. Their siblings had not grown up to replace them and, if they married, the main income source was gone." Others became self-combed because factories refused to hire those they feared might marry and give birth.

Liang Jieyun, 85, and Huang Li-e, 90, are rarities as zishunü and have never had a husband or children. Photograph: Tania Branigan for the Guardian

"Women were afraid of marrying a bad man," said Liang, adding that local men gambled and smoked opium. "If you got married, you had to give birth to children and raise them and work very hard for the family."

Women who married joined their husband's family, at the bottom of the hierarchy. "All their labour went to the in-laws and became their duty. The in-law family would never be grateful; it was what was supposed to be done. Their status was very low," said Ye.

In contrast, self-combed women could enjoy the gratitude of brothers and take pride in their contribution.

Because of their long working hours, factory workers often slept by their machines. In Zhaoqing, another town in the Pearl river delta, they lived as a community. Some are thought to have formed romantic or sexual relationships.

When the Wall Street Crash led to the collapse of the silk industry, many went to Singapore as servants. Huang spent decades there, sending money home to her brother and nephew. "We never thought about ourselves. We never did anything for ourselves," she said.

While some see the custom as a daring challenge to strict Confucian patriarchy, others think it more complex.

"Superficially, it looks very different to what we thought about traditional Chinese women. People tend to think it was a phenomenon of rebellion," said Ye. "It's true that women did choose to be zishunü. But almost all of them emphasised the relationship with their natural family and very traditional values such as filial piety."

The practice began to die out as the clan system disintegrated amid the turmoil of the 30s and 40s. The marriage law passed by the new Communist state in 1950 rang its final death knell by raising the minimum marital age, banning polygamy and forced or arranged matches, and granting women equality.

Some of Liang's peers married, but most of those who had taken the vow continued to live by it, sending home half their income or more. One sent 80% of her earnings every month, said Ye.

Decades later, some could recall each word of their letters from home: proof of a rare indulgence on the part of workers who otherwise scraped by. Illiterate, they paid other people to reread the letters until they knew them by heart.

The Hall of Ice and Jade was built to shelter the 'self-combed women' in old age, although it is now a museum. Photograph: Tania Branigan for the Guardian

With no pensions, some adopted daughters to look after them in their old age. Others sent home a portion of their wages to construct the red-tiled pillars and aqua arches of the Hall of Ice and Jade. It still holds the memorial tablets of the dead. Having left their families, their names could not stand alongside those of their parents.

But the last resident moved out years ago. Now Shatou's 10 remaining zishunü live with nephews and nieces or in care homes, with government allowances. Some of the 12 children Liang raised for employers come to visit her.

She feels no envy for today's women and their unimaginable choices.

"It's still hard to find a good man," said Liang. If a man is poor, his wife will have to struggle; if a man is rich, he may take a mistress, she said.

She leant forward.

"Good for you," she added. "You have an education, and you've travelled."

Additional research by Cecily Huang