When you buy this book you get an electronic version (PDF file) of the interior of this book. Become a master in solving Hyper Sudoku 9x9. After solving all the

When you buy this book you get an electronic version (PDF file) of the interior of this book. You can play the puzzles in this book on your mobile phone! Jigsaw

Also the puzzle may contain the regions of random (irregular) shape; this variant is called Jigsaw Sudoku