Playing is not just a fun way to pass the time, due to its logical elements it has been found as a proven method of exercising and stimulating portions of your brain, training it even, if you will and just like training any other muscle regularly you can expect to see an improvement in cognitive functions. Some studies go as far as indicating regular puzzles can even help reduce the risk of Alzheimer's and other health problems in later life. - 1000 Hard Jigsaw Sudoku Puzzles - Answers to every puzzle are provided. - Each puzzle is guaranteed to have only one solution. - Six puzzles per page (8.5 x 11 inches). -