Tag Archives: ALS-XZ

Badger’s Advanced Sudoku


This post highlights David Badger’s two advance puzzles in the Sudoku 1001 Hard Puzzles sysudokie review, both starting with the almost nice loops to be found along the XY railway. In 301, the black XY ANL removes two 7’s, and … Continue reading

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A Very Hard Finale with Ardv2 398


A hard basic leaves it to an unusual ALS to shake things loose, enabling an XY and a UR to wrap it up.  Maybe the hardest of the pre-selected Very Hard.   Line marking looks easy, until you look at … Continue reading

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A Closing ALS Postscript on THLS


This post demonstrates ALS-XZ as an alternative to hidden XY chains, and concludes the review of The Hidden Logic of Sudoku by Denis Berthier. In THLS, Denis goes outside the Royles 17 collection only a few times for illustrative examples. … Continue reading

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Hodoku ALS-XZ


For your after Christmas Sudoku fix, this post is about Hodoku’s ALS-XZ, a label favored by most writers. I prefer the term ALS toxic sets, associating the method with others by the goal of identifying a set of candidates guaranteed … Continue reading

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The ALS Jump Ball


The last review puzzle from the Weekly Extreme Competition, Wex 435, evades the Sue de Coq to give us: a precaution about grouped forcing chains in XYZ-wings, a genuinely extreme patterns trial, and an obvious form of ALS trial to … Continue reading

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Gordon Fick Tricks More Extreme 200


This post reports an alternative solution, without my pattern analysis, to Antoine Alary’s special More Extreme 200, based on a Sysudoku reader’s innovative use of a little known technique, the double common ALS pair. Two ALS sharing two restricted common … Continue reading

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