Sudoku X Puzzle Books with an X Factor: Includes Answers Thanks to Sudoku, you will never get bored. This book contains 150 Sudoku X Puzzles; there are two puzzles per page. The Sudoku puzzles contained in this book are standard Sudoku 9x9 puzzles with the added challenge of an X factor. At 6 x 9 inches (15.24 x 22.86 cm), this Diagonal Sudoku Book is small enough to fit in a bag or backpack, if you want to take it with you. The solutions are at the back of the book, six solutions per page. Exercise Your Brain with Sudoku Sudoku Puzzles are a fun challenge and improve your concentration skills. Solving Sudoku puzzles helps you keep your brain sharp and fit. You don't need to be a math geek to Sudoku! In order to master Sudoku Puzzles you only need to use logic. Sudoku GiftsA Sudoku book makes a great gift for anyone in your family or circle of friends that wants to learn to solve Sudoku puzzles and experience the challenge and joy of solving Sudoku.