Beginning Sudoku solvers often ask the question, how do you play Sudoku? Is there a logical way to get to the answer? The answer is yes. Sudoku solving is all about logic and pattern recognition.

where to start

Find the number with the most cells solved. The more cells resolved, the better. Use these resolved cell numbers in crosshatch form. By doing so, you are removing the columns and rows where that particular number may reside. This is a good way to find naked and hidden singles patterns.

Once you solve a cell, be sure to check the effect it has on other cells in the same row, column, or 3×3 box. Often, you will be able to use the solved cell and solve another cell.

pencil in candidates

Penciling candidates is a very useful technique. You can choose to enter only candidate pairs as needed, or enter all candidates for each unresolved cell. When you enter all the candidates, you should use candidate elimination techniques.

This is where knowledge of simple to complex patterns will help you solve for empty cells. Let’s say you have a matching pair of candidates 2 and 4 in two cells in the same row, column, or 3×3 box. You can use these two cells to eliminate the same candidates in any other cell in the same row, column, or 3×3 box.

The logic is simple. If two cells in a 3×3 row, column, or box are constrained to the pair 2 and 4, then one of the cells will be a 2 and the other will be a 4. You don’t know which at the moment, but it doesn’t matter. So you can safely remove candidates 2 and 4 from the same row, column, or 3×3 box where the pair resides.

You can use this technique for many patterns, including triples and quads. Sometimes it will be difficult to spot these patterns because other candidates in the cells hide the even, triple, or quad pattern.

There are more advanced patterns and techniques that you need to master to solve the fiendish Sudoku puzzles. Learn them, and there won’t be a Sudoku you can’t solve using logic and no guessing.

So how do you play Sudoku? By recognizing patterns, applying logic, and eliminating candidates, it solves cells one by one.