Yuen Wo Ping is the man who turned Jackie Chan into a superstar and made Keanu Reeves look like a kung fu expert. He tells Stuart Husband about his latest project, Crouching Tiger, Hidden Dragon

They call him Master Yuen - and so they should. Yuen Wo Ping is widely acknowledged as the world's foremost action choreographer. A veteran of 50 Hong Kong kung fu movies, he is widely credited with catapulting Jackie Chan to international superstardom with his first two films as director, Snake in the Eagle's Shadow (1978) and Drunken Master (1979).

But it is his airborne stunt choreography, known as "wirework", that has brought Wo Ping world renown. Not only does he make you believe a man can fly; he makes you believe he can glide, soar, hover, swoop, and all the other tricks in which birds had previously cornered the market. When you consider that he did all this for Keanu "I know kung fu" Reeves in The Matrix - 55-year-old Yuen's first Hollywood movie - the awesome scale of his achievement becomes apparent.

Yuen takes things a stage further in Ang Lee's remarkable fantasy epic, Crouching Tiger, Hidden Dragon, in which Chow Yun-Fat, Michelle Yeoh and newcomer Zhang Ziyi, as crusading 17th-century warriors, do battle across rooftops, over mountains and lakes and, in one remarkable sequence, while swaying in the tops of bamboo trees.

How did you get started in the business?

My family were all involved in Chinese opera, and my father, Simon Yuen HsaioTien, was a movie actor and stuntman. He was my trainer, my own master, if you like. I used to go to movie sets to watch him work and got involved in my own right as a stuntman and background fighter in old-style martial arts movies in the 1950s. In the early days, they always picked me to be the one to die first. I was very good at falling down dead.

How did you get into wirework?

The turnover in movies in Hong Kong is pretty fast, so you get to try out all kinds of different styles. I started off doing period movies, then cop movies with a kung fu flavour, then we went back to swashbuckling heroics, where you have a freer hand with the choreography; you can heighten the swordplay and make it more operatic. I am more into the softer styles, rather than the hard, fast cut-cut-cut of a lot of movies, so I use the wire to bring that out.

How does it work?

The actors have to wear a heavy canvas corset attached by metal cables to a wire, which hoists them 75ft in the air. These are worked by a team of "puppeteers", working in tandem with the opposing actor's team to avoid mid-air collisions. There is no computer trickery involved - the only "special effect" is when we remove the wire in post-production.

Would you say that you are the best wireworker in the world?

That's not for me to say. I've done around 50 movies now, but it would be wrong ethically for anyone in our field to compare themselves. We admire each other's work. There's no jealousy: if someone comes up with a great new movie, it inspires the rest of us to do better next time.

But you did 'make' Jackie Chan?

The movies I did with Jackie put him on the map, but that was mainly because we changed the genre a little by taking some of the grimness out that had been there since Bruce Lee. We made it more slapstick, more fun.

How does training Hollywood actors compare with working with Hong Kong actors?

American actors aren't brought up in the Hong Kong tradition: Jackie Chan or Jet Li will already know how to fight, whereas those in Hollywood have to be trained. For instance, it took four months to teach Keanu Reeves the techniques.

Kung fu has gone mainstream in Hollywood with movies such as Charlie's Angels. How do you account for its popularity?

I don't really understand why this has happened. I think it must be that audiences in the US don't see too many Hong Kong movies, and they're not familiar with this kind of movement. And when they do see it, they love it, and they want more of it.

Purists argue that the art of kung fu is being devalued because the likes of Keanu and Drew Barrymore claim they 'know kung fu' after a few months of training. Do you think this is the case?

I didn't work on Charlie's Angels, but I know that Drew trained for five months. But I wouldn't call it devaluation; it's just a different way of working. You tailor-make the movement to the physicality and flexibility of the actor or actress. You can't compare Drew or Keanu to, say, Jet Li, or Jackie. There's a huge difference there in terms of movement, and I think everyone realises that.

Have CGI and new technology changed the way you work?

The major difference is that they have extended the boundaries of what is possible. I can do movements now that couldn't be done before. There has also been a transformation from the short cut to the longer take, so you can see more of the movement in a single shot. In Crouching Tiger, when they start flying over the rooftops, you can watch their movements in single takes. The technique was probably tailor-made for this project. So maybe "evolve" is a better word. As for CGI, I never use it.

Have you done things in Crouching Tiger you've never done before?

The main difference was that I had a lot of time to prepare, which you don't normally get in Hong Kong, where everything is so rushed, so I was able to work with the difficulties of the movement on the wire, and work out how to extend the movements over the rooftops and in the bamboo forest. When I first started in films like Iron Monkey, I wanted the martial arts to be very down to earth. That's a more practical and realistic approach.

But in Crouching Tiger, I was trying to express the more magical characteristics of old-fashioned wu xia ["martial chivalry", a genre akin to sword and sorcery]. I still tried to incorporate some realistic touches, though. You might notice that they fly through the air, but for every leap they make they come back down to earth at some point. I knew that working with Ang Lee would bring out some incredible chemistry. He has strong ideas and I'm a great admirer of that.

How did you shoot the bamboo forest scene?

It was probably the hardest scene I've ever done, mainly because it was location work instead of studio work, so you couldn't put the usual precautions in place. You have to work out where to peg the wires in, try and find a supportive enough spot for the crane ... it's precision working. I usually have a team of 15, but for that scene it went up to about 40. If I'd had more time I'd have made it better.

How long would, say, the first swordfight scene take to shoot?

Ang Lee would tell me his requirements and I'd choreograph the scene in the studio. From conception to training to shooting, the whole thing would probably take about a week.

Are the actors ever spooked by the things they're asked to do?

It is normal to be scared of heights, of course, but we have very specific safety demonstrations to try and make the actors feel comfortable; safety is our first priority. If I'm not 100% focused every second, someone could end up dead. I'll work on the movement until I'm satisfied, and only then will I get the actor or actress involved. Crouching Tiger was only Zhang Ziyi's second movie, I think, but she'd been training with a coach for some months. Michelle Yeoh was already experienced in all kinds of movement. The biggest surprise for me was Chow Yun-Fat. He'd maybe only done one or two action films before, and it was his first time with wirework, but I was amazed. His movement was great. Maybe he saw a lot of Hong Kong movies beforehand.

Do you think you've advanced the art form in Crouching Tiger?

Again, it's not for me to say. It's a kind of trial, this movie. It's very nuanced, so it looks very different, and I tried to improvise a lot more on the wire, so hopefully it looks more artistic. Whether it's a "new way" or not is probably up to the future to decide. Basically on every project I just do the best I can. The director and actors are the stars, not me. If the market likes what I do, the boss will be happy. But even if it doesn't do so well, I know I've worked to the best of my ability.

 Crouching Tiger, Hidden Dragon is released on January 5.