Tag Archives: regular XYZ-wing

A funster Extreme 116 Labor Day Special


An effective bypass, and a simple uniqueness rectangle, and three choices to close down funster Extreme 116 early. Charles Timmerman’s funster Extreme collection is less than  extreme, but a good introduction to advanced solving methods. The basic work is easy, … Continue reading

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THLS Needs a Ride on the XY Railway


This post solves an XY-chain example to illustrate the simplicity and efficiency of XY-chains, as opposed to the rule based overcomplicated view of them in The Hidden Logic of Sudoku. From the first, this Sysudoku blog emphasized the fundamental nature … Continue reading

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Wex 431 Slips by Sue, but is Caught


Finally a Weekly Extreme gets through the Sue de Coq gauntlet. Or so I thought. But after a joyful romp into XYZ-wing technique, and coloring aided by pattern analysis, I get to demonstrate instead another resource of my single alternative … Continue reading

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Wings and Chains With the Gordon Guide


This post reviews the Chapter 9 of Peter Gordon’s Sudoku Guide, entitled Forcing Chains and Grid Coloring. The guidance is very limited, and what there is, promotes guessing as opposed to solving by logic. This verdict is confirmed in the … Continue reading

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Hanson’s Bent Naked n-Set


This post examines Bob Hanson’s Bent Naked Subset rules in Sudoku Assistant – Solving Techniques, and provides a more relevant rationale – and  a more appropriate name – for his technique. Also, XYZ-wings not covered by the BNS are identified, … Continue reading

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Regular XYZ-wings


This post explains how the regular XYZ-wing and WXYZ-wing make eliminations with toxic sets. Regular XYZ-wings are illustrated, and the XYZ form of the bv map is introduced. If you are following the Order of Battle, you should be returning … Continue reading

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