Frank Longo

Are you a sudoku warrior? Now you have an incredible opportunity to reach elite status and bask in the glory of completing some of the hardest sudoku ever constructed. For diehards only! These incredibly difficult puzzles are handcrafted for the sudoku warrior who dares to go where other solvers fear to tread. So, if you're armed with the highest-level strategies,...

Build up your sudoku skills from easy to expert! In this three-book series, each book helps solvers build their skills to progress from one level to the next. The puzzles in Skill Builder Sudoku: Easy to Medium start with sudoku requiring only the most basic techniques, such as scanning, one-choice, and elimination. Additionally, the book includes tutorials and strategy tips...

Build up your sudoku skills from easy to expert! In this three-book series, each book helps solvers build their skills to progress from one level to the next. Puzzles in Hard to Expert are the most challenging and will build on the skills learned in the second book, Medium to Hard. Each new technique, such as swordfish and grid colouring,...

Build up your sudoku skills from easy to expert! In this three-book series, each book helps solvers build their skills to get from one level to the next. Medium to Hard will build on the skills learned in the first book, Easy to Medium, gradually introducing more advanced techniques (like jellyfish and finned X-wings) alongside puzzles designed to hone those...

Watch out-these sudoku might crush even the most stalwart of solvers!

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...