Sudoku is the martial art of puzzles. This book presents a collection of energetic enigmas and numerical conundrums. It is suitable for solvers on the go and fo

Bring a new skill to the fighting repertoire: interaction.

Puzzles for the masters, featuring an array of Gordonian Rectangles.

Swordfish, the Gordonian Polygon, Alternating Digits, and Jellyfish make these sudoku super-hard!

With every puzzle requiring upper-level strategies, this collection packs even more of a punch than Beyond Black Belt Sudoku. You'll encounter common advanced t