Ninja Assassin Sudoku: Black Belt (Paperback)

Take your place among the finest puzzle warriors by solving these ultimate ninja sudoku. In order to reach the elite level of the assassin ranks, expert techniques - sometimes even used in combination - are a necessity. These fun cranium-crushers are among the toughest you'll find anywhere, requiring swordfish, XYZ-wings, alternating digits, extended Gordonian rectangles, and other tricky techniques. In order to maintain your superiority at this type of puzzle, avoid spies who want to know more about these invaluable methods. Solving the sudoku in this book will be rewarding and give you Black Belt status, the highest echelon.