Monthly Archives: January 2013

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 Avoidable Rectangle


In The Logic of Sudoku, Andrew Stuart introduces a UR method in which corners on one side are known values, i.e. clues, and remaining candidates are prevented from forming a deadly rectangle with these clues.  This is his Avoidable Rectangle. … 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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The Unique Rectangle


Here I will summarize for you the variations of the unique rectangle method, UR for short, as detailed in  the most complete sources I know of, the http://www.sudocue.net  solving guide, and  Andrew Stuart’s Logic of Sudoku.  Later posts will bring additional UR … Continue reading

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Mashing the BUG


Bivalue Universal Grave, the uniqueness method, requires knowledge, or at least absolute faith, that the puzzle has a single solution.  Coloring is a powerful analysis tool for the near BUG situation, making such knowledge unnecessary. A happy and prosperous New … Continue reading

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