The Official Utterly Addictive Number-Placing PuzzleKeep the lights on while tackling these all-new Easy to Medium puzzles that will tease your brain and keep you on your toes! More than just hours of entertainment, Su Doku engages your mind, improves your concentration, and helps you stay mentally fit. With 150 brand-new puzzles to complete, you'll become a Su Doku master in no time!