Are you a fan of the popular logical puzle that goes by the name Sudoku? Even if you’re not, the chances are you know somebody who is. Once hardly known outside Japan, this addictive brain teaser has become a common feature of newspaper puzzle pages all over the world.

Sudoku’s great success owes much o its simplicity. The game calls for neither mathematical ability nor general knowledge and there are just a few sentences of straightforward instructions to read before you can play. The only skill required is the ability to recognise the difference between nine different symbols, and these don’t even have to be numbers.

Some clever marketing has helped the game. Western newspapers worked hard at promoting the game. Without this, it is unlikely that it would have taken off and become quite such a runaway success. The game also benefited from its Japanese name that made people in many parts of the world believe on one leading website is anything to go by. Newspapers responded by coming up with new kinds of ligical puzzles, all with simple rules and Japanese names. But for true Sudoku fans, only the real thing will do.