Tag Archives: coloring trap

Softening left page ultrahardcore 353


Here is another puzzle the DIY oriented solvers suggest is too hard for human solving, even as the moves they find are too instructive to ignore.  This post gets quickly to ALS methods that demand exhaustive enumeration from the DIY … Continue reading

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UHC 309 Rounds the Bases


The ultrahardcore review solvers illustrate a diverse solution path, before and after AIC and cluster building. Here is the grid after the bypass and box marking. Beeby found a naked single SE4 in r8c7 in its basic. The Sysudoku Basic … Continue reading

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An ultrahardcore 221 ALS AIC Clinic


Continuing a solution path with a finned starfish (5 lines), Beeby carries us through an unlikely  series of ALS aided AIC, dancing around two stalled coloring clusters. The contest ends with regular AIC finally expanding and wrapping the clusters. Here … Continue reading

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UHC 177 Introduces a Beeby Option


This post gets left page ultrahardcore 177 to coloring with an interesting Sysudoku Basic and a kraken X-wing accessed with a recently added AIC option. Stefan Heine’s ultrahardcore 177 makes many left page concessions, but makes a fight of it. … Continue reading

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KDST 575 Highlights Box Marking


Box marking gets to shine in the redo of Super-Tough, volume 5, book 7, #5. Here is the grid after the relatively modest bypass. The fill strings show where 4-fills were examined, but only one was found. In this snapshot, … Continue reading

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Funster Extreme 18 Stays in the Lines


After a brutal encounter with the bypass, what’s left of funx 18 is riddled with bv. A cluster covering  half the grid expands with a trap to wrap a color and finish the puzzle. The post concludes with an update on … Continue reading

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Two of Rebecca Bean’s Less Extreme


Here the Rebecca Bean Extremely Hard review closes with a line marking finish and an easy coloring. The collection is far from extremely hard, if the sample of 12 pre-selected for this review is typical. On the way to line … Continue reading

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A Run Through Ardson’s Very Hard Volume 2


This post begins a review of A.D. Ardson’s Sudoku Very Hard Puzzles, volume 2. The review will cover 10 pre-selected puzzles from 400, every 40 starting with number 38. Well, almost. The puzzle at the end of the previous post … Continue reading

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Tough, But Not So Nasty


Continuing with the review of Frank Longo’s The Nastiest Sudoku Book Ever, a sysudokie faces another hard judgement on a Single Alternate Sue de Coq, in Nastiest 662. If the trial is archived, the puzzle withstands major blows before giving … Continue reading

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Hodoku Grouped AIC I


This post uses two grouped AIC ANL from Hodoku to illustrate how such chains are inspired and constructed. After the first, readers are challenged to try this approach on the following examples, with checkpoint to follow. I was prepared to … Continue reading

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