Let's play Sudoku X on a 9 x 9 grid! Sudoku X is a variation of the traditional Sudoku grid that must be solved using the rules of Sudoku with numbers 1 to 9 making sure the diagonal lines are also solved using the rules of Sudoku. This logic based number puzzle game using is super fun, kills boredom and is great for taking on the go when you travel by road, plane or train! Help your brain get smarter with this paper based Japanese number puzzle book. Sudoku X comes in 5 levels: Level 1: Very Easy Vol. 1 - 40, Level 2: Easy Vol. 1 - 40, Level 3: Medium Vol. 1 - 40, Level 4: Hard Vol. 1 - 40 and Level 5: Very Hard Vol. 1 - 40. Collect all 40 volumes of each level and solve them all! Achieve Sudoku greatness!