Monthly Archives: February 2017

Berthier’s xyzt Chain

Posted on February 28, 2017 by Sudent

This post concludes my reading of Denis Berthier’s The Hidden Logic of Sudoku, with two example puzzles to illustrate his xyzt-chain. While it is good to be aware of Berthier’s “t” versions of classic XY chains, I don’t recommend a comprehensive … Continue reading →

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Berthier’s xyt-Chains Rated Extreme

Posted on February 21, 2017 by Sudent

This post suggests a limited role for Denis Berthier’s xyt chain in human solving. I found no THLS examples of longer chains not requiring prior xyzt or hidden chains.The last prospect, Royle 17-33442 proves to be both unjustified and unnecessary. … Continue reading →

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An xyt Color Wrap

Posted on February 14, 2017 by Sudent

In the spirit of Valentine’s Day, I come across a coloring resource in Berthier’s xyt chain. The elaboration of Royle 17-20565 in Chapter XVII of The Hidden Logic of Sudoku is a challenge in itself. By the theory of looking … Continue reading →

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Berthier’s xyt-chains in THLS

Posted on February 7, 2017 by Sudent

Next we review the introduction of xyt-chains in The Hidden Logic of Sudoku. These are modified XY-chains which allow extra candidates in the chain cells, and unlike regular XY-chains, make eliminations regardless of whether the chain starting candidate is true … Continue reading →

Posted in Advanced Solving, Berthier, Extreme Solving | Tagged , , , , , , | 4 Comments