Series: Martial Arts Puzzles series

Go way beyond difficult, with the hardest, most brain-busting sudoku you've ever seen! Calling all sudoku-solving diehards: with every puzzle requiring upper-level strategies, this collection packs even more of a punch than our previous Beyond Black Belt Sudoku. Get ready, because you'll encounter common advanced techniques with curious-sounding names like XYZ-Wing, Finned X-Wing, Sashimi X-Wing, Swordfish, Jellyfish, Gordonian Rectangle, and...