Tag Archives: locked sets

Jacobs’ Sudoku for the Brave


Coming back to basics, this post reviews Charlie Jacobs’ collection of basic puzzles, Sudoku for the Brave. The book has no commentary at all.  Just puzzles and solutions. Charlie labels his 200 puzzles “Extreme”, but they don’t come close to … Continue reading

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Sudoku Assistant Finds Locked Sets


This posts discloses several significant omissions in Hanson’s discussion of locked sets, including his examples, in the report, Sudoku Assistant – Solving Techniques. A subtle and sometimes bungled task in basic solving is the discovery of locked sets or subsets. … Continue reading

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Suset Enumeration on Sue de Coq


This post demonstrates a systematic  enumeration of subsets in the line marking of the Sue de Coq debut puzzle.  More difficult units are resolved by the scratchpad suset algorithm introduced in the previous post of October 25, 2011. To checkpoint … Continue reading

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Subsets by Susets


This post explains the concept of locked sets, and the terms associated with them.  It suggests how to find them, and includes  a scratchpad version of a common computer algorithm for detecting them. A locked set is defined with reference … Continue reading

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Line Marking Follow Up Actions


This post describes the follow up to the candidate fill of each line in Sysudoku line marking.  This includes the marking of line slinks, checking for X-wings, identification of  naked and hidden singles, and marking of bi-value cells. It also … Continue reading

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