It would be hard to dream up a stranger combination of sports, but try telling that to 37-year-old German policeman Frank "Anti-terror" Stoldt, who is this week celebrating becoming the light-heavyweight chessboxing champion of the world.
Contests consist of alternate rounds of boxing and chess, with wins coming by way of knockout or checkmate. After 11 rounds the fighter ahead on points in the boxing gets the decision. Stoldt defeated American David "Double D" Depto with a seventh round checkmate to take the title in front of 1200 fans in Berlin.
Chessboxing is administered by the World Chess Boxing Organisation (WCBO), whose slogan is "Fighting is done in the ring and wars are waged on the board". You can view a video of Stoldt vs Depto on the BBC website.
In the new issue of New Humanist Sally Feldman takes a look at chess and the various intellectuals, exiles, misfits and tyrants who have made the game their own.