Touching documentary captures a Mosuo family's wrenching choice between the ways of the old and temptations of the new. Guo Shuhan reports

As workers lift wooden boards from the roof of the cottage, an old man sits inside by the fireplace, calmly chanting from ancient scriptures, oblivious to the falling pieces of wood. Outside, an old woman watches them with deep grief in her eyes, for the room being taken apart was once her bedroom.

Erche Pinchu's mother and her grandson in front of their house in Lijiazui village.

For the Mosuo people in Southwest China's Yunnan and Sichuan provinces, the flames in the family fireplace kept burning around the year in the granny's bedroom (or yimi in the Mosuo language), are believed to bring everlasting prosperity.

At the end of the demolition, the old woman steps up and puts out the fire with water.

"The deity who has been blessing our family will leave," she says, almost choking with tears. "I'm terribly sorry to my parents and ancestors. Money doesn't make sense to me."

The documentary, The Granny House Away from Home, captures the anguish the old woman experienced two years ago in Lijiazui village, Sichuan province.

The documentary is made by Erqing, also a Mosuo, and participant in the village video project sponsored by the EU-China Biodiversity Program. The project aims to show the nation's cultural and biological diversity through the eyes of the locals.

The Mosuo people are known for their matriarchal system, under which the utmost respect is attached to the senior-most woman in the family. It is her bedroom that serves as the family's center of everyday life.

The priest, or Daba, - a role that often falls on the oldest man in the family - makes offerings to the ancestors before every meal over the fireplace, called guozhuang, which is set in front of the altar. The fireplace is where all rituals - from celebrating births to quarantining the diseased - are performed.

In 2007, Dutch artist Mathilde ter Heijne and Tang Qifeng, co-organizer of Heijne's exhibition of Mosuo culture in Beijing, came to the village looking for a genuine yimi and offered 100,000 yuan ($14,600) for it.

Erche Pinchu, 35, and the oldest son of the family, saw it as a wonderful opportunity to turn around the family's fortunes.