Tag Archives: UR

David Badger’s 1001 Hard Sudoki


David Badger, a prolific composer of giant grid Sudoku puzzles, now has a giant book of 1001 standard size puzzles, self rated as “hard”. The publication date, listed in the back,  is June 17, 2017. Here is the standard Sysudoku … Continue reading

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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

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Longo’s Nastiest Ever After


This post finishes the illustrative review of Frank Longo’s The Nastiest Sudoku Book Ever, with review puzzles 673, 684, 695 and 706. The bv scan and occasional easy coloring continue to be enough for what Frank claimed to be the … Continue reading

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The Nastiest Ever Party II


This post displays some sysudokie snapshots from Nastiest 618, 640 and 651, The bv scan rules, with line marked fish, unique rectangles, Sue de Coq, XYZ-wings, and XY-chains.  A  Sysudoku technique formerly rated extreme gets to stop for a drink. … Continue reading

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Hodoku Unique Rectangles


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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Revisiting Wex 435


This post updates the Weekly Extreme Review with a revisit of Wex 435, a puzzle that proved resistant to the single alternate Sue de Coq and was deemed the toughest in the review series, inspiring an extreme ALS trial, the … Continue reading

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Trial 13 of Fata Morgana


This post checkpoints the third “figure 8” nice loop generated by the FM exocet, and follows up on the first, the exocet trial Cnp13 As to the homework, Yesss! It happens again. The FM exocet defines the endpoints of two … Continue reading

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