Expert Sudoku
Welcome to Expert Sudoku, where patterns give way to chains. Every puzzle here needs at least one chain of linked candidates, such as an XY-Chain or an alternating inference chain, or a move of similar depth such as Sue de Coq.
Techniques You'll Need
- XY-Chains
A chain of two-candidate cells, each linked to the next, whose two ends rule out a digit in every cell that sees them both
- Alternating Inference Chains
Complex chains that alternate between different candidates and different types of links to create powerful eliminations
- Sue de Coq
Two or three cells where a row or column meets a box, whose candidates split between that line and that box, clearing digits from both
Expert Challenge
These puzzles represent some of the most challenging logical deductions in Sudoku. You'll need to master multiple advanced techniques and often use them in combination. Expert mode puzzles require careful analysis, strategic thinking, and the ability to visualize complex patterns across the entire grid.