Download or read book Sudoku Book 300 Extra Hard Puzzles written by Sudoku Book and published by Createspace Independent Publishing Platform. This book was released on 2017-02-04 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 300 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.