Судоку The Times Difficult Su Doku. Book 4 [Collins ELT]

The eagerly-awaited fourth book in the bestselling Times Difficult Su Doku series. A collection of 200 previously unpublished Difficult Su Doku puzzles — perfect for the intermediate Su Doku solver in need of a constant supply of challenging puzzles. You are guaranteed hours of absorbing, brain-stretching entertainment. Since the first Su Doku puzzle appeared in The Times in November 2004, they have become a phenomenon, with over 5 million copies of The Times Su Doku books sold worldwide. You don't need to be a mathematical genius to solve these puzzles, it is simply a question of logic. Each puzzle has a unique solution — and theres no guesswork required. The Times Su Doku remains the original, the best and the market leader.