Featuring a huge number of Sudoku X puzzles, all carefully sorted into order of increasing difficulty, this unique collection of 200 puzzles is full of attractively-designed challenges from best-selling puzzle author Gareth Moore, author of many international books. In Sudoku X two diagonal constraints are added to regular Sudoku - now you must follow all the regular rules but also no number can be repeated in either of the two main diagonals. Printed on large, top-quality paper ideal for solving on, the 200 Sudoku X puzzles vary in difficulty from easy to hard so whatever your preference or experience you'll always find a puzzle here to suit you.