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slash podcasts. Hello and welcome to more or less on the BBC World Service.

I'm Tim Harford.

This week I pit my w wit against a math professor turned professional chess player.

John Nun. Now this was probably my first mistake. John Nun went up to Oxford at the age of

just 15 to read maths.

He became a math professor and then, in the early 1980s,

he gave it all up to pursue a career in chess.

At the highest point in that career John ranked a cool ninth in the world.

He's quite good. John has written numerous books on chess strategy and his latest,

John Nun's chess course, explains how the German chess world champion

and mathematician Emmanuel Lasker used logic to defeat his opponents in the early 20th century.

Chess and mathematics.

That suggested to me that perhaps the two of them are linked.

...