It's tricky, it's addictive and it will test your powers of logic - The Sun Su Doku is a serious workout for your brain with 220 puzzles with 3 levels of difficulty. Test yourself on the plane, daily commute or while relaxing on a sunny beach. Sun Doku is based on the Japanese puzzle Sudoku which roughly translated means `single number'. It has been the most popular logic puzzle in Japan for 20 years. It requires no calculations or knowledge of maths - it works pure and simply on logic and elimination. Here you have 220 puzzles with three degrees of difficulty - Teaser, Toughie and Terminator. Infuriating and compulsive but great fun.