Monthly Archives: November 2011

XY-Chains

Posted on November 29, 2011 by Sudent

This post explains the XY-chain, the most specific, easy to spot, and prolific of Alternating Inference Chains. It includes what many call the XY wing, as the shortest possible XY-chain. One XY-chain can generate multiple toxic candidate pairs. An XY-chain … Continue reading →

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Death Blossom Lite

Posted on November 22, 2011 by Sudent

This post describes and illustrates the Death Blossom with bv petals. It is most easily found as a secondary target while looking for XYZ-wings. Death Blossom Lite is a close, and easier to meet, cousin of the WXYZ-wing. First let’s … Continue reading →

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ER Winks, Forcing Chains and Irregular XYZ-wings

Posted on November 15, 2011 by Sudent

This post introduces “Empty Rectangle” weak links (ER winks) as a form of “seeing”. It is shown how the ER can be extended by a more general form, the forcing chain. It is also demonstrated that XYZ wings can be … Continue reading →

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Delta Sky Even More of a Challenge

Posted on November 10, 2011 by Sudent

Line marking was tough, and no UR showed up. removes 4 r2c2 for the above naked triple in the NW box. Quite certain that no XY ANL were available, I allowed Beeby UR, regular fish, and and simple ALS_XZ before … Continue reading →

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Introducing Advanced Solving Posts

Posted on November 8, 2011 by Sudent

My next series of posts describe and illustrate well known solving methods which I label as advanced, simply because they use the field of candidates discovered by basic solving techniques. These methods organize slinks (strong links) and winks(weak links) in … Continue reading →

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Thoughts on Sudoku Basic Solving

Posted on November 1, 2011 by Sudent

This post concludes my series of posts on basic solving, the actions taken to identify all candidates.  As  the October posts have shown, sysudoku basic solving also identifies and marks strong links and locked sets in boxes and lines.  It … Continue reading →

Posted in Basic Solving Procedures, Sudoku Toolware | Tagged , , | 4 Comments