Tag Archives: ultrahardcore review

Wrapping Up UHC 89


This post completes a coloring solution of Stefan Heine’s left page ultrahardcore 89.  Two examples of cluster exit AIC building bring a second finned swordfish, and a cluster exit wrap of the large cluster. After this follow up of last … Continue reading

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A Box ALS in Left Page UHC 89


In this post, a large box ALS with many outside candidates becomes a starter in AIC building, and a second cluster becomes a AIC target.  Restoring 2r8c7, we continue with an box ALS node AIC chain, using its 5 value … Continue reading

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UHC 89 Breaks Out from a Monster Basic


This post coordinates the two DIY solvers used in the ultrahardcore review, choosing and interpreting solver methods and ignoring some removals to match the Sysudoku DIY order of battle. A series of early moves breaks the ice for AIC building … Continue reading

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A UHC 45 Discontinuous Nice Loop Seminar


Heine’s left page ultrahardcore 45 offers a host of examples illustrating when a Beeby “discontinuous nice loop” is and isn’t a 1-way. Coloring closes the class. UHC 45 has a remarkable number of bv and line slinks, given the monster-like … Continue reading

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Pattern Analysis with Coloring on UHC 1


Coloring can be combined with freeform pattern analysis to determine a small set of pattern trials for Heine’s ultrahardcore 1. Typical choices for this decision are reviewed. A single trial produces the solution. For this we go back to the … Continue reading

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Single Alternate SdC on ultrahardcore 1


This post reports a rare outcome in an SASdC trial, the extra term carrying through to a solution. Here is the grid with NWc1 marked as a Single Alternate Sue de Coq chute. The contents of the wall can be … Continue reading

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Heine’s ultrahardcore 1 Starts the Review of Left Pages


This post whittles on a tough grid, duplicating results of the two solvers by different means. When the solvers stall, we find a Single Alternate Sue de Coq for readers to try. Sysudoku Basic brings four clues and  slinks, but … Continue reading

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Ultrahardcore Review ALS-wings V


This post completes a survey of ALS-wings in the review of Stefan Heine’s ultrahardcore collection. The study was to determine how ALS-wings can be constructed as ALS maps are built. This post covers five more examples in UHC 443 found … Continue reading

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Building the ALS-wings of UHC 3


This post begins a review of examples of ALS-wings from the ultrahardcore review. The review will illustrate a DIY strategy for constructing them, that is compatible with the concurrent ALS mapping and ALS_XZ building processes of the previous posts. Ultrahardcore … Continue reading

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Dov Introduces Lite Coloring of ultrahardcore 311


This post finishes the lite coloring revisit of past trials with Dov Mittelman’s lite introduction. It leads to a solution of Stefan Heine’s UHC 311 without trial. This puzzle occupied 3 posts in the ultrahardcore review, starting with November 3. … Continue reading

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