Tag Archives: APE

Pitkow’s Grand Master Sudoku


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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An Insane 445 Pattern Slicing Demo


In this revised post, difficult line marking leaves a semi-monster. It is whittled down to a decisive double ANL, which can be duplicated instructively by pattern slicing.  The review puzzle, Insane volume 4, book 4, number 5, with thousands more, … Continue reading

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Absolutely Nasty 4 Review Snaps I


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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Unit Forcing Chains


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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Coloring Sue de Coq and APE


Coloring is a general purpose weapon.  It limits the puzzle’s  ability to satisfy the restrictions imposed by  Sue de Coq and APE .  This explains why sysudokies  record the “almost” patterns found in the bv scan, and return to them … Continue reading

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Aligned Pair Exclusion (APE)


Happy New Year 2012!  I’m happy to be sharing my discoveries in this blog, and I can promise a more innovations in 2012. It’s about how we can best use our visual and mental abilities to solve difficult Sudoku puzzles.  … Continue reading

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