Monthly Archives: January 2012

Box/Line Reduction

In a box/line reduction, or “box/line” for short, a line’s candidates for a number are restricted to one box. That makes these candidates a toxic set, since one of them must be supplied to the line.  We can remove other … Continue reading

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Special X-chains

The “Special X-chains”  of the title are the names assigned to particular X-chains, like “skyscraper” and “2-string kite”.  You might think that it’s of value to look for them, but I disagree.  They just pop out at you when you … Continue reading

Posted in Advanced Solving | Tagged , , | 2 Comments

The X-Panel and X-Chains

We will now be leaving methods relying on the bv map as the primary visual aid. With puzzles that survive these methods,   we need to remember that the bv map file remains an important resource.  With every clue or candidate … 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

Posted in Advanced Solving | Tagged , , | 3 Comments