The perfect stocking filler for su doku lovers this Christmas. 200 quickfire Su Doku challenges, increasing in difficulty as you progress, designed to get the brain cells working. These mini puzzles are the ultimate short, sharp number-crunching workout. A compact puzzle gift book for everyone who enjoys a Su Doku challenge but doesn't have too much time to spare. Smaller grid sizes: 4x4 and 6x6. 3 levels of Su Doku are included with the solutions at the back of the book. Ideal for solving while travelling, on holiday or relaxing at home.