Hard to Extreme Sodoku Challenge for Master Players

Warning: this Sudoku book is not for the short-tempered. The patterns are more difficult to catch so losing your cool is a near possibility. But despite that, you should work hard to get all the benefits of the activity. Playing improves your number skills, concentration power and logical thinking skills too. There are several benefits of the game as well. Combined, these should encourage you to continue playing. Good luck!