Sharpen up your mind and improve your memory by playing Sudoku every day. Sudoku stimulates your mind, increases concentration and makes you feel happy by giving you a sense of accomplishment. It is said it can also reduce the chance of developing Alzheimers. This Sudoku puzzle book contains 400 puzzles with a single level of difficulty, so there are no wasted puzzles. There are 4 puzzles per page and solutions are at the end of the book.