I like Sudoku. I quite enjoy Sudoku, as, it seems, does a vast proportion of the British population. Various people have, in recent weeks, used up an awful lot of newsprint trying to look at why it’s so popular, trying to out-Sudoku rival publications, and none of it seems very satisfactory. I mean, they bang on about how it appeals to both men and women – as opposed to chess problems, which are primarily male, and cryptic crosswords, which in my experience appeals equally (and usually equally little) to both men and women, but I think they’re missing the point.

The reason it’s popular is that it isn’t a game. It’s an exercise.