127.0.0.1: Created page with "An '''Almost Locked Set''' is a group of '''N''' cells in a single house with candidates for '''N+1''' digits. In other words, it is one cell short from being..."

2021-10-25T09:09:13Z

Created page with "An '''Almost Locked Set''' is a group of '''N''' cells in a single house with candidates for '''N+1''' digits. In other words, it is one cell short from being..."

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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]].

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.

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.

== Usage ==
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.

The [[ALS-XZ]] technique uses only 2 Almost Locked Sets to perform eliminations. It is the most basic ALS technique.

== See also ==
* [[ALS-XZ]]
* [[ALS-XY-Wing]]
* [[ALS-XY-Chain]]
* [[Death Blossom]]
* [[Almost ALS]]

Almost Locked Set - Revision history

127.0.0.1: Created page with "An '''Almost Locked Set''' is a group of '''N''' cells in a single house with candidates for '''N+1''' digits. In other words, it is one cell short from being..."