The Official Utterly Addictive Number-Placing PuzzleThe season for fun--and Su Doku--has arrived! You're sure to get spring fever with these all-new Fiendish puzzles for loyal Su Doku fans. 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!