Tag Archives: Sudoku tools

The 2012 Akron Sudoku Tournament


I have to interrupt my review of forcing chains to celebrate the hugely successful, first time Sudoku tournament put on by my hometown Akron-Summit County Library.  Upwards of 50 solvers enjoyed three 20 minute rounds, followed by an exhibition of … Continue reading

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Casting for Regular Fish


How do you spot regular fish? An effective radar is the set of markings that you saw in the blank lines of the “Complementary  Swordfish” panel of the last post, repeated here: Looking from left to right, I marked the … Continue reading

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The Remote Pair – A Special XY-Chain


The remote pair comes your way with a blinking road sign. It is an XY-chain in which every bv along the chain contains the same two candidates, X and Y. The X and Y in the end cells are toxic. … Continue reading

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Riding the XY Rails


This post illustrates the complete enumeration of all XY-chains and toxic end pairs by drawing curves through the bv along XY-chain routes. XY-chains are then systematically divided into sub-chains with toxic ends. It’s a Sysudoku innovation. The puzzle is from … Continue reading

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Suset Enumeration on Sue de Coq


This post demonstrates a systematic  enumeration of subsets in the line marking of the Sue de Coq debut puzzle.  More difficult units are resolved by the scratchpad suset algorithm introduced in the previous post of October 25, 2011. To checkpoint … Continue reading

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