Sudoku is a nine-by-nine version of LatinSquares, where each "puzzle piece" is merely an identical three-by-three rectangle. The similarity ends there, really. No denying its popularity! Some advantages of LSQ over the competition:

 

    * These are free.

    * The variety of puzzle piece shapes adds some geometric reasoning.

    * They're small enough to take a whole page along, yet difficult enough to be absorbing. To me, Sudoku sometimes turns into a real slog.

    * There's a mechanical but fairly precise notion of difficulty level.

    * They're aesthetically more pleasing.

 

As against that, Sudoku is, well, more common. In the early days you could find it in Dell puzzle magazines as "Number Place", and more recently in the Penny Press magazines as "To the Nines". These days, you can find Sudoku, well, just about everywhere: even in the Financial Times weekend section!