Tag Archives: hidden UR

A Partial Pattern Trial on ultrahardcore 179


This post starts with the 5-panel freeform  analysis to compare with yours and then moves on with the partial pattern trial suggested in the last post, of 8 patterns containing 8r2c9. My 5-panel patterns are much less promising  than the … Continue reading

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Beeby Finishes ultrahardcore 91


The Beeby series continues on trial wounded ultrahardcore 91 until the expanding coloring cluster can  take it home. Is your trial-less solution ready? Next up t is  a 1-way from 1r6c3 that is exended back to 3r2c3 for a second … Continue reading

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Three Lucky Pandas


This post is a quick report on Lucky Panda Books 288, 336 and 384, with solutions similar to the five covered in the review. In 288, the bypass starts well on a 3-fill, but dries up fast.   A grid … Continue reading

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A Classic Insane 144


After the two Basic level 96 and 120, James Forest’s Classic Sudoku comes back with one puzzle, 144,  in the tradition of the KrazyDad Insane collection.  The bv are there, but it takes a few X-chain ANL to jar loose … Continue reading

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Insane 435 By Irregular XYZ and ANL


The third puzzle in a review of the KrazyDad’s Insane collection, Insane v.4, b.3, n.5,  succumbs to bv scan removals.  Some a bit unusual, but no new  ground broken.  The collection resides at http://www.krazydad.com . The updated basic trace includes … Continue reading

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Beyond the Rectangle


The alternative deadly uniqueness formations of the Sudocue Guide are detailed in this post.  Also, there is a UR checkpoint on Sheldon’s Master Class # 3 that goes beyond the UR cases surveyed in recent posts. I can’t leave the … Continue reading

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Stuart’s Hidden UR


In Logic of Sudoku, Andrew Stuart describes a unique rectangle with only one bv corner.  The tell-tale naked pair is not there.  Stuart calls this formation a hidden UR, with good reason.  You have to find the bv candidates in … Continue reading

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