Learn strategies to help you solve even the most difficult sudoku puzzles. Play Sudoku Play Sudoku Basic Strategies Singles in Rows, Columns, and Blocks Strategy Naked Pairs, Naked Triples, Naked Quads Strategy Hidden Pairs, Hidden Triples, Hidden Quads Strategy Pointing Pairs, Pointing Triples, Intersection Removal Strategy Box/Line Reduction Intersection Removal Strategy Advanced Strategies X-Wing Strategy Simple Coloring (Singles Chains) Strategy Y-Wing Strategy Swordfish Strategy Challenging Strategies X-Cycles Strategy XY-Chain Strategy 3D Medusa Strategy Unique Rectangle Strategy Hidden Unique Rectangle Strategy XYZ-Wing Strategy Utilities Sudoku Solver - Unique or Multiple Solution Finder Evaluate Sudoku Puzzle Difficulty - How easy or hard is it?