Wai won't reveal the tricks of his mask technique, but he changes faces in a flash. Donning the costume of a Chinese general in a video demonstration, he wears a mask portraying his character's sternness in one second and - with the flip of a long, wide sleeve across his face - happiness in the next.

Amiable and cheerful in his Tsuen Wan office bedecked with trophies and mementos from his shows, Wai explains how he's taken his act around the world for 20 years. He's performed for Chief Executive Donald Tsang Yam-kuen, Premier Wen Jiabao, Taiwan's President Ma Ying-jeou and actor Jackie Chan, but he rocketed to fame on CCTV in 2007 when he changed 44 faces in three minutes, and set a Great World Dsjjns record - the Chinese equivalent of Guinness World Records - of 58 face changes in five minutes in February last year.

Wai says he owes his success to the stage training he received as a youngster and the encouragement of his opera-performer father. Born in Nanning, in Guangxi province, by the age of 12 he was honing his Chinese opera, martial arts and acrobatics skills at the Guangxi Peking Opera Troupe. He later progressed to the Tianjin Opera School, spent his twenties as an actor and instructor at the Guangxi Peking Opera Troupe and in 1982 sought better prospects in Hong Kong.

Wai says his migration wasn't easy and that for a month he had to scavenge to survive. 'I didn't know anyone so I couldn't find any work. It was a very hard time,' Wai says.

Fortunately, he met an agent who found him work in the Song dynasty village, one of the attractions at the now-defunct Lai Chi Kok Amusement Park. Wai then found work as an extra and stunt performer in film and TV, working alongside the likes of Chan and Sammo Hung Kam-bo. In the late 80s, Wai established his own entertainment company and produced shows for tourists. When he searched for new ideas for his shows in 1996, he unwittingly rekindled childhood memories of his favourite bian lian performance.

'I suddenly remembered being in Sichuan watching Legend of the White Snake, in which the evil goblin constantly changed his appearance to display his moods during the battles with the white snake,' he says. 'It was simply amazing. Then it occurred to me that [this] was something I really wanted to learn, and it seemed a good time to do so.'

With the help of relatives and friends, Wai embarked on a painstaking search for a bian lian master. After many rejections, he managed to find one in Chongqing.

'It was hard to find a master because the art tends to stay within the family,' he says.

'I was an outsider to them. My master was an exception as we had a rapport.'

Wai says he learned all the skills in just three days. 'It's one of those crafts in which the skills are easy to learn, but hard to master,' he says. 'To make it a good show, you have to develop a strong sense of theatrics, style and movement, and [this] can only come from years of training and experience.'

Returning to Hong Kong, Wai became immersed in the craft and soon launched a new career as a bian lian master. But it wasn't easy.

'When I first performed, I could only change four faces, and there were embarrassing mistakes,' he says. 'Then I spent a lot of time and money on it, and lost sleep over it.'

Now a success, he wants to revitalise the art, which developed from 18th-century Sichuan opera, with innovations such as Western pop music.

'I use these new elements to attract the new generation,' Wai says. 'I hope they see my act and see that bian lian can be modern and fun, not something passe I want to promote this art.'

Wai has also opened up teaching the art. He once took on a protege from beyond his family, but the partnership did not last. So six years ago he made his daughter, Hathor Wai Fei-hung, his protege? even though women are traditionally banned from learning the art to stop its secrets passing to other families.

'There's nothing a woman can't do,' Wai says. 'We have to move with the times.'

Hathor had a series of odd jobs such as amateur singer, reporter and waitress before Wai sent her to learn the art in Shanghai.

'[The move] gave me a sense of direction and I discovered I belong to the stage,' the 29-year-old says. 'I wish I could have done it when I was much younger.'

Like her father, Hathor has modernised her act with Doraemon and Spider-Man cartoon characters, added homages to Michael Jackson and says she can also dance to hip hop and sing during her costume-changing acts.

'We'll tailor a show for the clients. I like the challenges involved,' she says.

Wai did not expect his son Wai Choi-hung, 22, to follow his sister's footsteps into bian lian.

'I didn't want them to do so because they'd have a tough life like me, but I changed my mind when I saw them show an earnest interest in it,' Wai says.

Choi-hung says he was spellbound by his father's stage act when he was a 14-year-old amateur magician, and learned bian lian five years later.

'But it's not just a magic trick. Bian lian is an art unto itself, and it's very vivid and striking. Magic is just part of it,' says Choi-hung, who now splits his time between performing and studying film and TV at the Academy for Performing Arts.

The hardest part of the act is not mastering the skills, but 'the waiting backstage, because we have to wear heavy masks and costumes, and it's suffocating and very hot', he says. 'It gets unbearable when there's a delay.'

Bian lian has brought Wai closer to his children, who lived apart from him for 15 years after his divorce from their mother.

'We spend a lot more time together and are just like friends,' Wai says.

Wai also plans to write a bian lian-themed story for TV 'to show it's an art, not just an acrobatic trick', he says. 'It's something that requires mystery and skill.'

But he wants nothing more than appreciation for his art.

'People call me a master now, but I don't want to be treated in a special way,' he says. 'I'm just a performer, like others. I've done nothing too extraordinary. I'm just good at what I do. As long as people show respect towards this art, I am happy.'