Challenge yourself with 200 tricky Su Doku puzzles.A collection of 200 puzzles which are perfect for the Su Doku solver who is looking for one step up from the very basic Su Doku puzzles. If you are in need of a supply of more challenging puzzles, these are guaranteed to provide 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 there's no guesswork required.The Times Su Doku remains the original, the best and the market leader. The puzzles are provided by Wayne Gould, the man who started it all.