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How to play Sudoku
In which I solve an EXTREME SUDOKU for Twitter
Techniques for Hard Sudoku
Y-wing (XY Wing) - an Advanced Sudoku technique
X-Wings and the Rectangle Rule for Solving Medium to Hard Sudoku Puzzles
How To Do Hard Sudokus In 10 Minutes
Tutorial #40 A must know technique. NOT a puzzle.
How to Solve a Sudoku Game