Category Archives: Heine

Ultrahardcore Review ALS-wings II


The  ultrahardcore ALS-wing survey continues with examples from UHC 47. The survey illustrates how ALS-wings are found as ALS are added to ALS maps. Continuing the survey into a second review puzzle UHC 47, the reward is this well laid … Continue reading

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Continuing the Box ALS Scans for UHC 311


This post continues with the box to box, row and column scans for ALS_XZ.  The C and S ALS fit into one red/orange cluster with a trap. The clusters meet in cell r7c8, showing that blue or orange or both … Continue reading

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Building ALS Maps With Suset Tables


This post displays the ALS map for rows of UHC 311, at the moment when the Beeby solver returned the first ALS_XZ. The suset ALS marking and building aid is introduced, and suset tables for rows, columns and boxes are … Continue reading

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An Error Hides a Lite Coloring Trap on ultrahardcore 399


This post corrects an error on the post of December 8, that prevents a lite coloring trap in ultrahardcore 399. Then there’s follow up on the trap, with the lite coloring marking in place. Trial is not avoided, but the … Continue reading

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Pattern Trials Peel the UHC 487 Onion


The ultrahardcore review ends, with Stefan Heine’s 487 giving up a naked single and two skyscrapers, and a jaw dropping complex 1-way, shuts down the solver team. Slicing at it with three onion peeling pattern trials leaves very little for … Continue reading

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SASdC Unlock UHC 443 for Beeby


After the hidden unique rectangle hinted last week, a pair of Single Alternate Sue de Coq trials gets the review solver Beeby moving again. ALS-wings and a finned X-wing get us to a colorful finish. The hidden unique rectangle left … Continue reading

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Beeby Softens Up ultrahardcore 443


This post reports a series of Beeby ALS-XZ featuring alignments in Z and X, almost to the point where a trial is needed. A simple basic trace means a hard start, with a crowded grid. Sudokuwiki’s 579-wing is a Beeby … Continue reading

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Lite Coloring Informs a UHC 399 Trial


In one post, the 10th ultrahardcore review puzzle is wrapped, but not without an introduction of something new in Systematic Sudoku. Ordinarily advanced steps begin in line marking, and lite coloring is introduced. In line marking Stefan Heine’s ultrahardcore 399, … Continue reading

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An SASdC Trial Defeats ultrahardcore 355


In this post a SASdC trial plays like a regular hard puzzle from other collections. The trial amounts to adding two clues, and seeing  what happens.  But it isn’t guessing, and instead of making a small gain, the trial solves … Continue reading

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UHC 355 Provokes a SASdC Trial


After a typical ultrahard Sysudoku Basic, Sudokuwiki starts with an APE so unusual as to change my working definition of the APE. APE stands for Aligned Pair Elimination.  From every example so far, I thought it was the two elimination … Continue reading

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