Tag Archives: hidden unique rectangle

Systematic FTSPAH 44 and 84


This post demonstrates two more FTSPAH unlikely to frustrate anyone following the Sysudoku order of battle. FTSPAH 44 begins with an unusually large number of givens, which generates a correspondingly large number of 3-fills. In fact, the givens offer both … Continue reading

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Lucky Panda 240 Rides Nice Loop Coloring


The candidates of a nice loop form a coloring cluster. This review puzzle from the Lucky Panda Sudoku review illustrates a decisive nice loop coloring. Two hidden UR 2 show up as well. After a productive bypass and box marking, … Continue reading

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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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