Apologies if this piece is not up to my usual exacting standards but my nose hurts, on account of having been punched by a German policeman in Berlin. This should not necessarily be taken as a reflection of German policemen. We were both wearing boxing gloves at the time; we had also just started a chess game. This is not easy to explain. Where to begin?

Possibly in September 2003, when the Berlin-based Dutch artist Iepe Rubingh unveiled chess boxing to the world in an art gallery called Platoon. Styling himself "Iepe the Joker", he took part in a demonstration fight against a Dutch friend called "Luis the Lawyer". Two months later, they fought again in Amsterdam, this time for the vacant world middleweight chess-boxing title. Vacant because they were the only two middleweight chess boxers, indeed the only two chess boxers, in the world.

Rubingh won a dramatic encounter. "I had a pretty terrible position on the board so in the last round I tried to knock him out," he recalls. "He only just managed to stay on his feet. The bell went and he put his hands up in the air but he couldn't find his corner. He was really dizzy but we still had to play the final round of chess. There was a clear win for him, but he just couldn't figure out the right moves."

Chess boxing is precisely that - a sport that combines chess and boxing. There are six rounds of chess, each lasting four minutes, and five of boxing, each lasting two minutes. The rounds take place alternately, beginning and ending with chess, with one-minute intervals. You win by a knockout in the ring or checkmate on the board. In the event of a draw in the chess and no knockout, a points winner can be declared on the basis of performance in the ring. At least I think those are the rules; I, too, was feeling a little dizzy after my trial fight.

Rubingh's inspiration to create the sport came from Yugoslavian artist Enki Bilal's comic book, Cold Equator. "When I was 17 or 18 I read this book, which was part of my father's comic collection," he says, "and it always stayed in my mind. Bilal stated that chess boxing in the future would be like this - a 12-round heavyweight boxing fight and then a game of chess, which can last up to five hours. That's not very public-friendly, so we started working the idea out and slimmed it down. We want to combine both sports as closely as possible and have a balanced rulebook, so that either chess or boxing can force the decision. We want the sports to be as important as each other."

Chess boxing started with an artistic impulse. "Chess boxing breaks certain rules," explains the 31-year-old Rubingh. "We tend to divide everything into different worlds, but in my opinion worlds are much more connected than people see them at first. Chess boxing breaks through this habit. So many people say to me: 'Chess and boxing, they just don't fit together,' and some chess players hate the idea, but they forget that former world boxing champion Lennox Lewis and current champion Vitali Klitschko both play chess. Boxing is about the control of aggression, and chess boxing is 200% about the control of aggression."

Somewhere along the line, however, Rubingh's interesting artistic exercise has turned into a full paid-up sport. At first, I think he is pulling my leg - as well as flattening my nose - but by the end he has convinced me that he is determined to establish chess boxing as a global sport. Iepe the Joker has turned into Iepe the Entrepreneur, setting up the World Chess Boxing Association, franchising the idea in Bulgaria, planning fights in Tokyo and New York, preparing to open a chess boxing gym in Cologne, and now looking towards France and the UK.

Last month, a Bulgarian called Tihomir Titschko - a very strong chess player and decent boxer - won the European heavyweight chess-boxing title in a contest in Berlin that was given huge publicity in Germany. The appeal, to the media anyway, is precisely that of the perceived difference between boxers and chess players. Despite the example of Lewis, we see boxers as lithe killing machines and chess aficionados as fat blokes in anoraks who push bits of wood around in the smelly back rooms of pubs. Chess players, surely, are prize nerds.

"Partly that's true, but partly it's not true," says Rubingh. "I've met a lot of non-nerdy chess players. Professional chess players these days tend to do a lot of physical working out. They've learned that it's not about sitting in a bar drinking coffee or alcohol and smoking, and that you get your best game on the board when you're in shape. Players such as Vladimir Kramnik and Garry Kasparov have for years had their own physical trainers. They're full sportsmen, they train a lot, they're physically in good shape; mentally, of course, they're in great shape. Playing makes you tired and they sweat and their pulse rate is going up when they get excited. They lose one or two kilos during a game."

Rubingh now runs a chess-boxing club at a gym in a trendy part of the old east Berlin, and that's where I will face policeman Frank Stoldt tonight. What in boxing they call "the tale of the tape" is not heartening. Stoldt is 35, had 12 proper amateur fights in his 20s, winning 11, and has an Elo international chess rating of 1,700 - good club standard. I am quite a bit more than 35, have only once been in the ring (in 2000) with a heart-attack victim who boxed for exercise and had been told not to hit me, and might on a good day manage an Elo rating of 1,500. Today is not a good day.

"Don't worry," Iepe the Joker tells me just before the match. "I have instructed him not to hurt you. Not to really hurt you." How I wish he hadn't added that qualification. How I wish, too, that an hour ago, just off the plane, I hadn't eaten a "Kraut Hot Dog" - sausage, sauerkraut and lashings of mustard - and a pizza. Frank has legs made of tungsten and is skipping furiously. I have just tried on my yellow satin boxing vest for the first time for five years; it is so tight I can't breathe and it takes me 10 minutes to extricate myself from it. "Usually we weigh in before the fight," says Frank, "but I don't think we will with you." The psychological battle has begun.

I'd like to be able to blame the boxing for my impotence on the chessboard, but can't. I play a wretched opening and am in trouble even before we climb through the ropes. Perhaps I play too aggressively, hoping for a quick checkmate before the boxing even begins. I certainly underestimate Frank's chess, and that may have angered him, because within about three seconds of the start of the first boxing round he has landed a humdinger of a punch - I don't see whether it is a left or a right - on my nose. It starts bleeding and I lurch backwards. "I didn't realise we were taking it quite this seriously," I say pathetically. "This is a contact sport," says Iepe, offering me a towel for my nose and telling me not to sniff.

After that, Frank takes it more easily - concentrating on body punches and just giving me the occasional cuff to the head. I manage to brush his shoulders a few times. Even if he stood still for long enough, I don't think I could punch him in the head. I fear I lack the natural aggression that fighters require, though I can sublimate it through chess. Or maybe I just don't want to provoke him further.

Frank is in complete control on the board, too. I'm convinced he could finish me off quickly, but instead makes sure we box all five rounds before I lose in the final chess round. Whether this is a thoughtful gesture to ensure I get the full chess-boxing experience or just sadism, I don't know. "How did I do?" I ask Iepe. "On a scale of one to 10, you rate about three," he replies. The Dutch are noted for their directness. "Come and have a drink," I suggest to my opponent after the contest. "I don't drink," he says and goes off to do some chess theory with the club's resident chess expert. These guys are serious.

What started as art really does seem to have been transfigured into sport - Rubingh hopes to attract high-class chess boxers and stage regular title fights under the auspices of his association. How does a radical performance artist whose oeuvre includes blocking off intersections in Berlin and Tokyo to create monster traffic jams (he was jailed for 10 days for his Japanese provocation) justify such a departure?

"I don't care any more," he says. "I can see both. If I talk to a sports magazine, we just purely talk about the sport; if I talk to an art magazine, I explain my views [about pigeonholing in society]. But the interest to me now is to put the ideas very deep into society, because as soon as you put the label 'art' on it there are a lot of people who have a scary reaction. They say, 'Art, that's too difficult.' So I search for other ways to spread my ideas in society, and chess boxing seems to be one way to do it." Oh, he hopes to make some money out of it, too.

Above all, he is attracted by the degree of self-control the fighters/players have to exercise. "After a boxing round your heart will be beating, your adrenaline goes up and it's very difficult to concentrate on a chessboard," he says. "The first chess-boxing test that we ever did, I just gave away my queen immediately. I said, 'This is not going to work out, people can't do chess boxing.' But then the second test that we did, it was already a little bit better."

For my match, he advises me to take it slowly when we resume playing chess after the boxing and to check my first move three times before playing it. In fact, I am so dazed and so annoyed by my wretched position that I can barely bring myself to move at all and eventually lose on time - the most un-heroic of conclusions.

He says audiences for the title fights have been surprisingly enthusiastic. "I wondered if they would concentrate and try to follow the game, or go to the bar to have a beer when the chess started. But it turned out that everybody was very interested. When the boxing comes they get very excited, and then, like the players themselves, they have to concentrate on the chess, look at the video screen and listen to the chess commentator. The public has this very dialectic evening." I didn't quite understand that either, but it sounds good.

Rubingh, with his pyramidal hair, shapes like a cross between Don King and Marcel Duchamp and becomes very voluble when envisaging the possibility of getting Lennox Lewis back into the ring for a chess-boxing match with Vitali Klitschko: "It would be as big as the Rumble in the Jungle, it would go down in history, we will offer them $15m." If he can stop the traffic in Tokyo, perhaps he really can get the chess-loving former and current world heavyweight boxing champions back together. Don't bet against it. I have a nose for this sort of thing. Or I used to.