The American's fascination with China started in college, where he majored in Chinese studies. His first trip to Asia was in 1972, followed by a master's degree in Chinese at Columbia University, which included a year in Taiwan studying the language.

'The US didn't have diplomatic relations with China at that time, so I went to Taiwan,' says Cohn. 'I started collecting folk art, woodblock prints - anything authentic. My interest has always been in vernacular art. It was what I could afford.'

Cohn first encountered Han embroidery when he operated tours throughout China in the late 1970s and early 80s. Tourists wanted to buy souvenirs, but this was difficult with the lack of appropriate items at state-run Friendship stores.

'A lot of people were interested in buying embroidery because there was nothing else to buy,' he says. 'It was one of the first items of commerce that seemed to exist outside the state system. The material seemed to be an incredible bargain and a great storehouse of folk and local culture. For me, it was fascinating, deep and varied.'

Cohn started to collect in 1984. The bulk of his collection dates from between 1850 and 1920.

'There was a blossoming of embroidery across China during this time, due to the lower price of silk,' says Cohn. 'Later, when women began going to school and didn't have time to embroider, the tradition began to die out. This body of material represents a late age in Chinese imperial life.'

Cohn says the best works from Shaanxi and Shanxi provinces also yield fine embroidery, due mostly to their dry climates and a well-developed merchant class.

Although embroidery also existed in the south, the wet winters of Shanghai, Guangdong and Hubei encouraged mould that damaged the textiles. Most of the Han embroidery in Cohn's collection uses silk threads on silk fabric. The background might be backed with paper to give it stability, or made with the aid of a hoop or embroidery frame.

According to Cohn, minorities embroider textiles differently from the dominant Han.

'The whole purpose of the cloth for minorities groups - the different costumes and colours - is to distinguish themselves from each other. There are extremely distinct geographical styles for each ethnic group, and the subgroups within them. How this developed, I don't know, except from intense isolation from each other. You may also say the higher up the mountain, the better the minorities' embroidery.'

Unlike Qing dynasty Han embroidery, minorities' work tends to be on cotton or ramie instead of silk. Looms are set up in ways that make their weavings resemble embroidery. The results are a hybrid of weaving and embroidery. Minorities' colour application generally isn't as subtle, with shaman-like clothing that depicts a unique sense of humour. Han embroidery is more mannered, however, with carefully controlled facial expressions in characters and gentle gradations of tones.

Cohn says he hopes that his exhibition will inspire more people to treasure the lost art of embroidery. His dream is to put together a collection to be exhibited on the mainland.

'It feels right to let Chinese people have it and see it,' he says. 'A textile is both a commodity and a work of art. There's a lot less abstraction involved in textiles than in fine art.

'It has much more to do with daily life and daily habits. It's an art form that has rules. Collecting embroidery is like letting a person move in with you.'

Threads of Meaning, Fri-Sun; talk by Don Cohn on collecting in China, Thu, 5.30-6.30pm, Cloth Haven, 7 Upper Station St, Sheung Wan, Inquiries: 2546 0378