Hook or X-Y Wing rule
As a last resort for solving difficult puzzles having tried everything else, the Hook (or X-Y Wing) may come to the rescue.
Copyright © 2005-2011 Sudoku Dragon
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Hook or X-Y Wing ruleAs a last resort for solving difficult puzzles having tried everything else, the Hook (or X-Y Wing) may come to the rescue. Copyright © 2005-2011 Sudoku Dragon |
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