Tag Archives: hidden unique rectangle

Only Extreme 304 is AIC Level


This post and the next update Castillo’s Only Extreme Sudoku review with a solution of OnEx 304 without trials. Most of the solution path is in AIC building, the most challenging level of Sysudoku Advanced. The only move prior to … 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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