Solving Sudoku: Basic Tips
Some sudoku puzzles can take hours, or even days, to solve. Each puzzle has only one solution that can be found using logic. The following tips will help you solve any sudoku puzzle:
- Start with basic logic. You know that you cannot repeat any number in any row, column or block. Knowing that, you can use the pre-filled numbers to help you begin filling in the empty squares.
- Look for definites. Definites are numbers that are definitely in a square. This may not always work when starting more advanced puzzles, but it can used with any difficulty level.
- Start at 1. Beginning with 1, work your way all the way through to number 9, filling in as many squares as you can for each number. As you progress through the numbers, number placements will become more obvious.
- Eliminate. If you find two squares in the same row, column or box that must be one of two potential numbers, then you can eliminate those numbers elsewhere. For example, in one block you have four empty squares. The numbers 3, 5, 7, and 9 are candidates for squares A and B, while 7 and 9 are candidates for squares C and D. Squares C and D must contain 7 and 9, so squares A and B cannot. If C and D are also in the same row or column, then you know that no other squares in that row or column can be 7 or 9. You have also narrowed squares A and B down to 3 and 5.
- Pencil marks. Use pencil marks to help you remember what numbers could be in a square. If you are working on several empty squares with more than two candidates, or if you have to walk away for some reason, it is possible that you will forget which numbers you are looking at for a given square. Some sudoku solvers lightly pencil in the numbers, while others use a series of dots in which the position of the dot indicates the number.
- Double check. If you get stuck on a sudoku puzzle, regardless of the level, go back and double check your answers. You may find a mistake in your logic. Typically, however, you will find pieces of the solution that you missed earlier. Finding one missed answer could be all you need to finish solving the puzzle.
- Learn strategies. There is a wide variety of sudoku strategies, and they all work to complete a puzzle. Learning a few of those strategies can make it easier to solve any level. Try these Sudoku tips
- Time. Remember that all sudoku puzzles take time. The most difficult puzzles can take days to finish.
The best way to learn how to solve sudoku puzzles is to practice, or try using sudoku puzzle software. Many newspapers offer daily sudoku puzzles, and the difficulty level increases through the week. You may not be able to solve the puzzles every day when you first start, but you will notice that you are able to get farther through the hardest puzzles each time.