Sudoku puzzles are a proven method for enhancing logic skills. As a logic puzzle, Sudoku is also a great brain game. If you play Sudoku every day, you'll soon begin to see improvements within your concentration and overall brain power. You could reduce your probabilities of Dementia or Alzheimer's simply by solving Sudoku puzzles. By using this selection of sudoku puzzle books you would experience enhanced brain capabilities for example focus, logical thinking and memory. This book contains 300 Sudoku X puzzles in Hard Difficulty. Sudoku-X follows exactly the same guidelines as the standard 9x9 Sudoku puzzle, with the only difference is the cross of shaded squares running from all of four corners to the center square, which should also contain one instance of the numbers 1-9. The goal of the puzzle is to complete the blank squares with the correct numbers. All rows, columns, boxes and also shaded diagonals should end up containing all of the numbers from 1 to 9. Each number can only appear once in a row, column, box and shaded diagonal line. To assist you on the way, a few of the cells have already been filled in with a number. 300 X Sudoku book puzzles in Hard Difficulty 4 puzzle per page An answer key for every sudoku puzzle Puzzles are printed on high quality white paper, format size 8,5 x 11 inches Perfect puzzle book as a special gift Choose your book today by clicking on the BUY NOW button at the top of this page.