Dong women embroider with just a single needle and without a fixed pattern, using their stitches to express their feelings for their children. The Dong people of impoverished Guizhou province have no written language, but their textile craftsmanship is unmatched in its refinement, and is a clear communication of love.

Wu crowns her daughter with the golden headdress. Her thumb and index finger, normally used for rough, heavy work, caress every strand. Everything fits. Her face softens and the deep lines that have come from hardship are recast with the dignity of sacrifice.

One of the 56 officially recognised Chinese ethnic groups, the Dong present such an outfit to one of their own during an auspicious event in the young adult's life. Three events are paramount: giving birth to a male, building a house and assembling one's coffin. But for Xia and her mother, today is that auspicious day they've been waiting for; Xia is leaving for university. The outfit transforms the young woman, as her academic progress is likely to transform her family and, in a small but significant way, her lush, remote mountain village, Dimen.

Here, centuries-old traditions are disappearing as fast as the motorways and train tracks make their way to Guiyang and Lhasa.

households, has no school. As a child, Xia walked two hours along mud paths to her primary school every day. Teachers spotted her talent early and sent her to the county high school, reachable only by bus. Since the family could not afford transport, she boarded at the school and came home during term breaks.

Xia excelled and, after graduating, she returned to Dimen, where she worked on the family farm and waited for a letter. When it arrived, so did Xia's unexpected future: the prestigious Guiyang University had accepted her to study food science. The news surprised Xia, but not her mother - who was determined not to repeat her life's biggest mistake.

A decade earlier, Wu's first daughter, Nong, had been just as successful in school as Xia. But although secondary education is free in the mainland, the family withdrew Nong from school because they could not afford her bus fares or books. Nong's teacher visited the family home several times, pleading with the Wus to find a way, insisting that Nong could one day go to university. But Wu said it was impossible and Nong, then 14, returned home sobbing on her last day of school.

A week later, Nong left home with five former schoolmates and a fake ID in search of work in Guangdong province.

Wu swore her three other children would study, but her husband offered no support. So she took on the burden herself, leaving home for two months at a time to carry timber, eating and sleeping in the mountains. Her mother's earnings - five yuan (HK$6) a day - allowed Xia to complete high school.

Xia received one academic award after another. Wu calculated the cost of her daughter's success and knew she had to be bolder. Sending Xia to university would cost 60,000 yuan over four years, an astronomical sum for a family that earned no more than 1,000 yuan a year.

In 2009, Wu, like most people of working age in Dimen, headed to the prosperous coastal provinces in search of work. She found a job cutting plastic sheets in a building-material factory in Guangdong, earning 1,800 yuan a month and sharing a dormitory with seven other women.

When Wu learned of Xia's acceptance to university, she felt euphoric, but also experienced "deep guilt and regret" for having failed her first daughter. She pushed those feelings aside and took a 10-day holiday, to rush home and celebrate with Xia.

to Dimen, there were few people her age to welcome her. Officially, 2,380 people live in the village, but about 60 per cent of them live as migrant workers in distant provinces, says Ren Hexin, director of the Dimen Dong Cultural Eco-Museum. The 1,000 who remain are very old or very young, and grandparents look after the children. With this exodus, traditions quickly erode. Singing, for example, has for centuries been the way Dong people communicate, but now you hardly hear it. Paper-making, weaving and embroidery are all crafts that may die with the older generation.

The history of the Dong, who are said to have originated in Dimen, goes back more than 1,000 years, to the Tang dynasty. Stunning wooden flower bridges, named after the exquisite sculptures that adorn them, criss-cross the Dimen river. Four-storey-high bell towers stand as testament to the village's unique heritage. On a warm summer's day, children swim in the river that curves through Dimen, which means "place with endless spring water" in the Dong language.

Houses here are constructed according to ancient blueprints. Architects and workers build a house in a stack, like collapsed dominos. Men gather wood from the nearby mountains, saw pieces and knock them together - without nails. Once the stacks are assembled, at dawn, the owner summons all his male friends and relatives to help pull up the structure. Within a few hours, the skeleton of a house is erected. A spiritual leader slaughters a chicken and sprays its blood on the main plank and a feast for those who helped follows.

The houses are built closely together around drum towers, octagonal pagodas modelled on a cedar tree. The scent of food permeates every lane and friends tend to come and go, tasting one another's fish dishes. Among the houses, grain stores are perched on stilts above artificial ponds, which deter rats and help prevent loss by fire - a fate suffered last month by another Dong village in Guizhou, Baojing, and a risk seared into Dimen's collective memory.

In the early hours of a cold April morning in 2004, an old man dropped his quilt onto the burning charcoal that kept him warm. The fire, stoked by the night wind, spread fast through his neighbours' wooden houses. The Wu family fled just in time but had to watch as their home succumbed to the flames. Xia recalls her parents' "terror, screaming and deep sorrow". Though no one in the family died, they lost almost everything, including ornamental garments that had been passed down through generations. The outfit that had been made for Xia was among the few possessions that survived - and that's because it had been kept at a grandparents' house.

That wasn't the first time the family had lost their home.

Under the mainland's family-planning policy, couples in rural areas are allowed to have two children. Many people hope for a boy to help with the farming. Wu bore two daughters, Nong and Xia. She tried again, had another girl, and was fined. In 1999, Wu had a fourth child, this time a son. But the joy of his birth was marred by pain and fear.

When the authorities had learned Wu was pregnant with her fourth child, they had come to her house and insisted on taking her away for an abortion. Being six months into her term, she fled into hiding. Her husband watched as the authorities tore down their house in retaliation, taking away all their belongings. He felt his head "explode", he says.

, is now a lean and sulky teenager who can usually be found wearing a blue tracksuit and slippers. Ahead of Xia's celebrations, his father takes Cheng to the woods with a harvest knife to mark the boy's coffin tree.

When a Dimen boy is born, the family elder designates a small tree that will grow up with him as his protector. As it is with men, it is with trees: the best ones are unbending and strong. Cheng's grandfather selected his tree, which stands near the top of a mountain overlooking the village. Tradition dictates that when a man reaches 40 or 50 years old, his tree will be made into coffins for him and his wife, and stored under their house. Children play and women wash clothes alongside the coffins in Dimen. To the Dong, life and death are part of the same natural rhythm.

Wu Xuezhen, grandfather to the Wu children, oversees much of the life and death in Dimen. He serves as the village's most venerated healer, fung shui master and fortune teller. In his mid-70s, he wakes up each morning to villagers queuing at his door, looking for various remedies. He blesses weddings, divines locations for new houses and gives astrological advice to businesses. He accepts small sums of money, but often none at all. He wants "to build karma for the future generations".

The grandfather draws on various sources of help when healing, treating simple ailments with mountain herbs and acupuncture. He can appear unorthodox; when a woman visits with a skin problem on her neck, he rubs alcohol on the flesh and sets it on fire. When a child faints, he applies spiritual magic to a cup of mountain spring water, takes a sip and spits it in the boy's face. When a task proves too challenging, though, he asks the ghosts for help.

An elderly woman with a child strapped to her back seeks Grandpa Wu's aid for her daughter-in-law, who suffers from fever and exhaustion but works in a factory in Jiangxi province, 1,000 kilometres away. The elder clutches a thick wad of paper, sets it ablaze and swirls it around, summoning the ghost of the patient's grandfather to help. "Her grandfather is working on it right now," he assures the worried woman, as he packs her off with a gentle smile, declining her money.

On the day of Xia's celebration, Grandpa Wu dispatches his patients early so he can prepare. He begins by bringing a pig's head across the Dimen river to the temple. He thanks the heavens and asks the village god to protect his granddaughter on her journey. He carries the pig's head home, where some 80 guests fill first the living room, then the television room and the bedrooms upstairs. When the village chief arrives, he has nowhere but the front yard in which to squat.

The Wu family serves a traditional feast in Xia's honour. Fish, which the Dong people raise on rice seedlings in the paddies, is roasted in hay, spiced with chilli and seasoned with mountain herbs. Guests enjoy an abundance of spicy green vegetables, braised pumpkin and handmade tofu. Farmers in Dimen don't use pesticides or chemical fertilisers, they say, because their children eat the crops.

The meal's highlight is , a delicacy reserved for special occasions. Fresh pork is marinated in vinegar, salt and chilli and pressed under heavy stones inside a barrel for three years, until the meat is pink, tender and extremely tasty. The is paired with a bowl of rice spirit for each adult at the party. The drink, about 35 per cent alcohol, is made from boiled, glutinous rice and distilled in wooden barrels for a week.

Guests segregate by sex in different rooms and everyone sits on child-sized chairs in circles around the food. Most of the guests are elderly and clutching grandchildren, feeding and pampering them on behalf of the in-between generation that is earning money in the cities. The celebration lasts from morning until midnight, with a few rest breaks in which women prepare further rounds of food and men sleep off hangovers.

, Xia's mother is preparing to return to Guangdong. She gives Xia an envelope filled with cash, equivalent to six months of her salary. With the university spending money settled, she leads Xia into the long-locked room to reveal the beautiful dress she made 19 years ago and the headpiece passed down from her own mother. Xia turns to thank her with a kiss; it's the first she's given her mother since childhood. Wu weeps but, unused to displaying her feelings, she wipes her tears away in one stroke and nudges Xia out of the room. Wu locks the door.

When she leaves, Wu takes the only key with her. The room, and its treasures, awaits the next celebration.

For all the ritual, Xia's departure to the big city is unceremonious. At 5.30am, she puts on a white embroidered shirt her mother wove for her, lays her oversized teddy bear on her pillow and drags her suitcase out of her house. She walks to the village bus station alone.

Grandpa Wu heals neighbours, Xia's father washes his clothes and

her little brother has darted off on a family errand. The one person who would have taken Xia all the way to university is toiling for her in a factory in Guangdong.

This is Xia's first trip of any distance, and on roads that aren't difficult, narrow and prone to landslides. As the vehicle approaches the gleaming new national highway to the provincial capital, Xia's eyes dart from left to right. Incredulous, she asks other passengers if all four lanes head in the same direction.

She will miss no one from Dimen except her mother, she says, and has no plans to return. "Maybe in 10 or 15 years," Xia muses. "But not until they build a good road there."