Board in the ring? It's chessboxing.

Andreas Dilschneider was still thinking about his opening moves on the chessboard when his opponent rushed up to him and punched him. Several times.

Mr. Dilschneider didn't complain. It was all perfectly legitimate. He threw a few punches of his own. When he got back to the chessboard, he was laboring and the adrenaline was pumping. He tried to keep calm and avoid hasty moves. Four minutes later, it was back into the boxing ring again.

Welcome to chessboxing, a young and intriguing sport that prides itself on its incongruous mix of muscle and mind, the pawn meets the brawn if you like. Think jab with your right, counter with your queen.

The rules are simple: six rounds of speed chess interlaced with five three-minute rounds in the ring. Each competitor has 12 minutes in total on the chess timer. Victory is by knockout, checkmate or resignation, or failing any of those, by points-based scoring system.

If it sounds surreal, it is to a certain extent. But it is growing in popularity, particularly in Germany, eastern Europe, and Russia.

And this weekend, an American will compete in the World Championship Final for the first time when David Depto, a pharmaceutical salesman from San Francisco steps into the ring to take on Frank "Anti Terror" Stoldt, a German, in an arena packed with perhaps 1,200 devotees.

"At the beginning, people thought it was absurd, but we are getting bigger and bigger and starting to work in a commercial direction with sponsors," says Dilschneider, a contender for the European crown two years ago.

Subtlety and belligerence

He says the attraction lies in the apparently contradictory combination of the belligerent science of boxing with the intellectual subtleties of chess.

The rapid movement from one to the other poses problems.

"The problem is adrenaline," he says. "It can bring you to the point of overestimating positions. After the first boxing round, don't make fast moves – try to slow down. And try to make the last move before the boxing so your opponent has to make the first move afterward."

Depto, a pharmaceutical salesman who has boxed for 12 years and played chess since he was 6, says it's no good being very strong at one discipline and weak at the other.

"If you are weak at chess, you will get checkmated quickly and if you are weak at boxing, you will get knocked out quickly," he says on the eve of his title fight.

The concept was the brainchild of Iepe Rubingh, a Dutch artist who took the idea from a comic, Froid Equateur. The first bouts, staged five years ago, were more performance art than sport, but the oxymoronic nature of the contest has caught on.

Stephen Moss, a British journalist and chess enthusiast who endured one chessboxing bout – and is unlikely to repeat the experience – says the combination of sports is not so incongruous.

"I don't know if it will catch on, but it's not as ridiculous a combination as you might think," he says. "There is a machoness about chess that people don't realize. The same sorts of emotions are driving those who do both. Both are battles to the death, kill or be killed, and it could all change in the space of two or three moves."

Move over, ultimate Frisbee

Chessboxing is not the only example of old disciplines being meshed and combined into new concepts.

Ultimate Frisbee and roller hockey have long since penetrated the mainstream. But out at the margins, other alternative sports are cropping up all the time, and it's remarkable how many people play them.

A quick trawl for examples produced blokarting (yachting on land), blackminton (badminton at night with flourescent body paint), tchoukball (a version of handball), urban golf, and street luge (self-explanatory and ill-advised).

Octopush is underwater hockey, a seemingly silly notion until you realize that as many as 2,000 people play regularly in Britain alone.

"It's a very fast-moving game," says Phil Lawrence, an octopush devotee. "We ran a few after-school sessions with kids. Within two months, we had 30 regulars."

He says the game is even bigger in Australia and New Zealand.

But why do sports morph and change and reinvent themselves like this?

Mr. Moss argues that every sport is in a kind of Darwinian struggle with other sports for survival. "When one sport gets boring they have to change the rules."

For Depto, it's simpler than that. "It's human nature," he observes, "to want to come up with something new."

OK then, iceketball anyone?