Author Archives: Sudent

About Sudent

My real name is John Welch. I'm a happily married, retired professor (computer engineering), timeshare traveling, marathon running father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. The blog is about Sudoku solving. It covers how to start, basic solving to find candidates efficiently, and advanced solving methods in an efficient order of battle. It is about human solving methods, not computer solving.

An ALS Toxic Set Update


This post reviews Sysudoku history on the problem of spotting ALS toxic sets, and presents the updated  recommendation in the ALS Toxic Set page just completed for the Guide.  This spotting process, to be referred to here as ALS partnering, … Continue reading

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A WXYZ vs. BARN Settlement


In this post, progress is reported on the Sysudoku Guide, and on  a possible territorial agreement between the WXYZ wing and the Bent family. The Guide, that link up there on the menu bar, is taken shape. The Basic pages … Continue reading

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Departing Highlights on Bean’s Extremely Hard Sudoku


It’s time to wind up the volume 10 review, with a few highlights behind the review table. The first one is the very unusual basic trace of IV-12, the homework puzzle of the previous post. You have the characteristic Extremely … Continue reading

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Bean Gets No Second Extreme


This post describes how I-41, in Extremely Hard v. 10 by Rebecca Bean comes close, but fails to force a deferred Single Alternate Sue de Coq trial. It does force a review of AIC hinges and grouped forcing chains. Here … Continue reading

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Colorful Trials for Bean’s Extremely Hard v.10


This post calls on pattern directed coloring trials to solve IV-24, a puzzle in Rebecca Bean’s Extremely Hard, vol. 10. This one that seems to defy almost all advanced methods, and therefore, to deserve the rank of “extreme”. This also … Continue reading

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Almost Extreme Bean ExHdv10 II-29


Here we have a regular XYZ wing with two irregular victims, multiple coloring clusters and wraps, one, by an AIC almost nice loop. Rebecca Beam’s Extremely Hard v.10 II-29 is borderline extreme. Basic is tough, but routine.   Except for … Continue reading

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The Volume 10 Rebecca Bean Extremely Hard Sudoku


This post begins the second review of a Rebecca Bean collection, this one prompted by a clever cover, and similarities in format to recently reviewed collections attributed to Moito Publishing, A.D. Ardson and James D. Glover. Here we resolve Extremely … Continue reading

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