# Tag Archives: The Hidden Logic of Sudoku

## THLS Needs a Ride on the XY Railway

This post solves an XY-chain example to illustrate the simplicity and efficiency of XY-chains, as opposed to the rule based overcomplicated view of them in The Hidden Logic of Sudoku. From the first, this Sysudoku blog emphasized the fundamental nature … Continue reading

## The Limited XYZ-wings of THLS

The XYZ-wing is limited in The Hidden Logic of Sudoku, as it generally is in Sudoku literature, by  a limited conception of the weak link.  This post presents a resolution of Royle 17-12407 using an iXYZ-wing, a form of the … Continue reading

## THLS vs. Unique Rectangle

This post updates the UR chart, with credit to Denis Berthier, then debunks another unfortunate THLS pronouncement. The homework puzzle illustrates another penalty a human solver pays for interpreting  The Hidden Logic of Sudoku as solving advice. Now in our … Continue reading

## Suset Jelly in nrc Space

Here we work through an advanced supersymmetry example from The Hidden Logic of Sudoku, without the symmetries.  The humanly practical tools of Sysudoku are entirely adequate to the task. The theme of this review is that the burdensome emulation SudoRules, … Continue reading

## Fishing in Lake Supersymmetry

This post reveals that the symmetries and supersymmetries of THLS, as applied to subsets and fish, are identical to a Sysudoku tool that reduces these Sudoku entities to numerical input for a well-known algorithm.  This shows conclusively that maintaining extra … Continue reading

## Hidden Logic Box/Line Interactions

This post looks at the brief and very late THLS treatment of box/line interactions in rc space. I say late, because box/lines (1/31/12) are essential in basic marking of candidates. But in The Hidden Logic of Sudoku,  box/lines are introduced … Continue reading

## Hidden Logic Symmetries of THLS

This post explains SudoRules’ complementary grid transformations that, as The Hidden Logic of Sudoku demonstrates in many Royle 17 examples,  converts hidden line subsets into naked line subsets, and box subsets into line subsets. Of possibly more interest to sysudokies, … Continue reading

## Naked Singles in SudoRules

This post reveals how naked singles are produced, in Berthier’s rule hierarchy of increasing logical complexity,  by single rule that is a member of the set of rules for every resolution method. This explains why number scanning candidates, and maintaining … Continue reading