Tag Archives: forcing chains

Decoding Hodoku Chain Notes

Posted on September 29, 2015 by

This post comments on the first part of the Hodoku “Chains and Loops” page. It reveals the premise dependent view of chains to be based on computer coding, and unsuited for human solving advice. It explains Hodoku’s chain notations as … Continue reading →

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Hodoku Unique Rectangles

Posted on September 8, 2015 by

This post lists the Hodoku UR techniques in a convenient reference sheet, and illustrates many of the examples in a more explicit Sysudoku format. I review Sysudoku principles for UR exploitation, and call attention to the Hodoku omission of forcing … Continue reading →

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Hanson’s Polarity ANL

Posted on August 12, 2014 by

This post reviews the section of Bob Hanson’s Sudoku Assistant report titled Almost- Locked Ranges. It presents an effective solving idea, but with hazy definitions and a confusing name. Here I identify this idea as a familiar one in the … Continue reading →

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Pitkow’s Grand Master Sudoku

Posted on January 21, 2014 by

This is a short review of the GM section of Sudoku vol. 3 , by Xaq Pitkow, published by Chronicle Books.  The puzzles vary between basic and moderately advanced levels I pre-selected 10 GM and 25 Super GM puzzles for … Continue reading →

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Paul Stephens’ Extremes Review

Posted on May 28, 2013 by

Here we review as one collection the “extreme” puzzles in Paul Stephens’  two current books, Mastering Sudoku Week by Week and The Sudoku Addict’s Workbook. In Stephens’ Weeks, puzzles for weeks 26 through 52 are labeled “Extreme”.  By this, Paul … Continue reading →

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A Bv Scan of Week 48

Posted on April 23, 2013 by

Here we checkpoint the sysudoku bv scan on the blog homework puzzle, Week 48 in Paul Stephens’ Mastering Sudoku Week By Week.  The scan includes Sue de Coq and APE, two techniques ignored by Stephens’ books, and two techniques, XYZ-wings … Continue reading →

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Absolutely Nasty 4 Review Snaps I

Posted on March 5, 2013 by

Here we link back to advanced solving posts as we enjoy sysudokie solving snapshots from the review table puzzles 0f Frank Longo’s Absoutely Nasty Level 4 (AN4) collection.  Did you ever get trapped looking at a neighbor’s vacation slides ?  You … Continue reading →

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Forcing Chains in Sue de Coq Analysis

Posted on December 18, 2012 by

In this post, the classical forcing chain and a sysudokie endorsed application are demonstrated on a multiple solution puzzle. An underlying assumption made in solving a Sudoku puzzle is that it has one and only one solution.  Some composers offer … Continue reading →

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Unit Forcing Chains

Posted on December 11, 2012 by

Here I explain why sysudokies pass on Andrew Stuart’s Dual Unit Forcing Chains.  We also examine a triple unit forcing chain from Unsolvable 40. As of this post, this statement continues  to appear  in Andrew’s sudowiki.org introduction to Unit Forcing … Continue reading →

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ALS Merged Cell Forcing Chains

Posted on December 4, 2012 by

This post demonstrates the merger of cell forcing chains by means of ALS nodes.  I  checkpoint  three triple cell forcing chains from the challenge of the previous post, and argue that comprehensive search for cell forcing chains beyond the dual level … Continue reading →

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