The New Sudoku Players' Forum

[bradles]

Simple Sudoku suggests *7* can be excluded based on colors. I've used "a" and "b" as the representation of different colors. However, looking at the problem, I thought with colors, that you couldn't make a decision on which one was true or false until you had two of the same color in one box? Can someone explain how this one works?

Code: Select all

 *--------------------------------------------------*
 |                |                |           7    |
 |      7a        |           7b   |                |
 |           7b   | 7a             |                |
 |----------------+----------------+----------------|
 |       7b       |  *7*       7   |                |
 |            7a  |   7        7   |                |
 |                |                | 7              |
 |----------------+----------------+----------------|
 |                |                |      7         |
 | 7              |                |                |
 |                |      7         |                |
 *--------------------------------------------------*


[vidarino]

We know that 'a' or 'b' must be true, and the cell in question can "see" a candidate of each color, and therefore can not contain a 7.

[TKiel]

The cell marked with the * shares a row with a b cell and a column with an a cell, one of which must be true. It doesn't matter which is true or which is false, but one of them must be.

Tracy

[bradles]

Awesome...thats perfectly explained.

Thanks.