WHEN JIANG ZEMIN heard Xuan Ke's orchestra for the first time in 1999, China's strongman was so enthusiastic that he broke with protocol, took to the stage and picked up a flute. He played traditional favourites, tunes from the old days, one after the other. Stunned by this unexpected performance, the orchestra stopped playing and listened. It was a memorable event for Xuan, who once spent 21 years in a mainland labour camp. His decades-long struggle to preserve traditional Naxi music - ethnic tunes from south-west Yunnan - was finally being lauded by those at the top. Today, Xuan is a maestro, musician and master of ceremonies. 'Welcome! Are you listening to my orchestra tonight?' his voice booms through the concert hall in Lijiang. Every evening, his troupe fills a wooden hall built in the traditional Naxi style, and Xuan himself swaps his jeans for a Chinese qigai. Just two weeks ago, he brought his show to Hong Kong's Academy for the Performing Arts. It was Xuan's second Hong Kong visit; the first being in 1997 during the last weeks of British rule. The energetic 74-year-old is half Naxi himself. The ethnic-musicologist inherited an interest in foreign languages from his Naxi father, a merchant who was an interpreter for the US Army during World War II. From his Tibetan mother, a singer, he inherited his high cheekbones, shock of unruly hair and passion for music. Linked to Tibetans, the Naxis are an ethnic group of 300,000 people in Yunnan and Sichuan. The biggest Naxi settlement is around Lijiang, a town protected by Unesco as a cultural heritage site. Naxis are known for their matrilineal culture and their unique pictographic script which is still used today. They practise the Dongba religion, which blends Lamaist Buddhism and Taoism, with some influences from Islam. One of Xuan's virtues is his outspokenness; but he has paid dearly for it. When he was 28, Xuan was already making a name at the prestigious Central Symphonic Orchestra in Beijing. But when Mao Zedong invited intellectuals to voice their thoughts freely as part of the now-infamous 100 Flowers Movement in 1957, Xuan joined the chorus who criticised the system. Like hundreds of thousands of them, Xuan found himself branded a rightist and was sent to a labour camp, where he spent 21 years. Music helped keep him sane while behind bars. Deprived of the right to play any music, he used to silently remember the melodies his mother sang, and the classical works he learnt in the conservatory. 'I could spend hours looking quiet; but in my mind, I had a full orchestra,' he says. He also tried to compose. 'Often, the ditties I made up were total nonsense but they kept me going.' By the time he was released, Dr Xuan was 49. 'At that time, I hated big cities because they had been the source of my troubles. All I wanted was to return to the simple life of my hometown.' He found the cultural scene in China had been devastated. In Lijiang, Mao's Red Guards were trying to eliminate all Naxi customs, which were regarded as 'feudalistic thinking'. Xuan felt an urgency to recover this lost heritage. 'I felt so desperate, seeing that all our cultural heritage had been wiped out,' he says. 'Those versed in Confucianist studies or Naxi ancient music belonged to the wrong social class. They were landed gentry and scholars, branded exploitative during the Cultural Revolution. So they were killed.' But he soon heard about a small group of musicians who played at burial ceremonies in the countryside. According to custom, the relatives of the deceased had to wail non-stop for three days. In order to fulfil their duty without hurting their throats, the kinfolk hired musicians. The reedy sound of the ehru was used to simulate the family's sorrows. Xuan attended the next village funeral. Seven old men were sitting by a coffin, playing the most mournful music he had ever heard. Xuan was ecstatic. 'It brought me great joy to hear them,' he says, 'It was also painful to see such a rich heritage reduced to [being performed] beside coffins.' The lives of those survivors mirrored his own hardship. Most had been banished to the mountains to be re-educated by the Red Guards. Some had been tortured. Xuan joined these forgotten masters. The group received no salary for their performances but at least the musicians were invited to share the food with the families of the deceased. Gradually, as former musicians were released from prison, the troupe increased to 21. Before long, the musicians started to play at happier events such as weddings and birthdays. In 1981, Xuan founded the Association of Dayan Naxi Ancient Music. 'I used the old term 'yue', meaning 'arts association', as used in Lijiang during the Ming Dynasty to represent a gathering of gentlemen, well-versed in various arts,' he says. The association's means were modest. While a good amount of money has been spent to preserve Naxi heritage (the old town of Lijiang, flattened by an earthquake in 1997, was fully restored at great expense), the authorities put music further down on their list of priorities. The troupe now comprises 25 members. 'Each elderly musician is a walking repository of our musical heritage,' says Xuan. Some of the instruments are typical for classical music; others have been specially adapted for Naxi use. Some are centuries old. An antique pipa was said to have been given to the Naxis by a musical virtuoso disguised as a ragged beggar in the early Qing Dynasty (1644-1911). Even older is a bowl bell, which dates back about 600 years. The other instruments include a Chinese zither, lute, flute, ehru, dihu (which produces a deep, low sound like a cello), 10-cloud gongs more than 200 years old and a bamboo huqin with a human-like face. Says flautist Yang Zemin: 'When playing those instruments, we sit still like Buddha, and forget our daily lives as we immerse ourselves in the music.' Still, the clock is ticking, and the main danger facing Naxi music is a lack of a new generation to take over from the old. The pictures of deceased musicians stretch the entire length of the Lijiang stage, where the troupe performs nightly. The oldest musician is 92 and in early December, one of the pioneers passed away. A few youngsters have joined the troupe. It takes years to train them to the classical repertoire, which is not written but transmitted orally. Thanks to his knowledge of English, Xuan is the Lijiang contact for most ethnologists studying cultural diversity in Yunnan. His name started to appear in overseas newspapers in the 1980s. His popularity eventually attracted Beijing's attention, but this time, in a positive way. Jiang's request to be entertained by the orchestra was like a national endorsement for the association. 'By his presence, the chairman gave the message that Naxi music is an integral part of China's cultural heritage,' Xuan says. 'He encouraged us to persevere in our purpose to save it and bring it to international audiences.'