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| − | An '''Almost Locked Set''' is a group of '''N''' [[cell]]s in a single [[house]] with [[candidate]]s for '''N+1''' [[digit]]s. In other words, it is one cell short from being a [[locked set]].
| + | #REDIRECT [[Almost Locked Set]] |
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| − | The simplest '''ALS''' is a single cell with 2 candidates. In a standard Sudoku an ALS can have a maximum size of 8 cells with 9 candidate digits.
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| − | It is not easy to spot a large ALS, but there are often a lot of these sets present in the grid. [[Bivalue]] cells are always easy to spot with [[pencilmark]]s.
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| − | == Usage ==
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| − | There are several [[solving technique]]s that make use of Almost Locked Sets. Any move that would eliminate all candidates for a particular digit from the ALS automatically forces the remaining digits to be locked in the group of cells. This the equivalent of a [[strong link]], which can be used in [[chain]]s and [[loop]]s.
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| − | The [[ALS-XZ]] technique uses only 2 Almost Locked Sets to perform eliminations. It is the most basic ALS technique.
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| − | == See also ==
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| − | * [[ALS-XZ]]
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| − | * [[ALS-XY-Wing]]
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| − | * [[ALS-XY-Chain]]
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| − | * [[Death Blossom]]
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| − | * [[Almost ALS]]
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