Single In Row |
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| Single In Row | |
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This technique is based on the fact that every row must contain every value once.
When there is only one cell in a row that can contain a value, this value can be safely assigned to that cell. In many occasions this technique can be used without knowing every candidate value. In the example below number 1 can be safely assigned to the yellow cell. This is because every row must contain one cell with the value 1. The red lines indicate the cells that cannot contain a 1 because this value is already present in the column. The cells with a red dot cannot contain a 1 because this value is already present in the box. Therefore, the yellow cell must be 1. 
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In the example on the right, you can see all the candidate values. The highlighted cell is the only one which can contain a 3 in this column. Therefore this cell must be a 3, since every column must contain a 3. |
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