SuDoku How to Play Guide

Only a brief introduction to SuDoku puzzle solving is given here. A very simplistic approach is presented based on a standard 9x9 puzzle grid from SuDoku One. The same techniques apply for SuDo12's 12x12 puzzle grid.

Let's learn by playing an easy level puzzle. We generate one by selecting Game->Easy from the SuDoku One menu.

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The following shows a SuDoku One generated puzzle.

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There are many ways to solve the puzzle but start by noticing that several 3x3 boxes already contain the number 4.

Look at the highlighted box. It must contain a 4, but it is already present in the highlighted rows and columns. The only square it can possibly go is circled. If the 4 were placed in any of the other blank squares it would contradict the rule that each number only appears once in each row and column.

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Another 4.

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There is nothing special about the number 4. The same logic applies with any number. For instance 3.

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Another 3.

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Another 3.

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A 7.

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A 1.

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Another 3.

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The last 3.

We have now finished the 3's. There is one and only one in each 3x3 box, each row, and each column.

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A 4.

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The last 4.

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Another way to locate numbers is when all others are already present in the same row or column.

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Or same row, column, and 3x3 box.

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The circled squares now have only one possibility.

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Let's fill them in.

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This has updated the situation so that now the circled squares have only one possibility.

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Let's fill them in.

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Using the same techniques it's now trivial to complete the puzzle.

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