Will Shortz Presents Hard Sudoku Volume 4 : 200 Challenging Puzzles

The next in our new series of only the toughest puzzles for serious sudoku solvers!

Do you have what it takes? These 200 challenging sudoku puzzles from Will Shortz will keep your mind sharp!

Features:
- 200 hard puzzles
- Big grids for easy solving
- Introduction by legendary Puzzlemaster Will Shortz