Sudoku is a game of logic and numbers. No special mathematical skills or calculations are needed to solve the puzzles.
Below are several techniques to help you solve sudoku puzzles.
1) Don’t guess. Only enter a number if you are sure that is the only possible number that can go in that space. Sudoku is not a guessing game but rather a game of logic. There is only one correct number than can be entered into any particular cell.
2) Use elimination. When starting a sudoku puzzle, you will generally determine the first numbers using elimination. Here’s an example. Start with the number 1. When you see a 1, you know that another 1 cannot be in that same row, column or box. By knowing where another 1 can’t go, you can often determine the only place it can go.
3) Start with the givens. Most players prefer to start by working with the number that has the most givens. For example, if a puzzle has a lot of 3s, there is an excellent chance you can complete more 3s using elimination.
4) Make notes. Pencil in possible entries for a cell. For example, you may know that one particular cell must be either an 8 or a 3 but can’t determine which one is correct. Pencil that information in the cell. This information often will help you solve other cells in the same row, column or box.
5) Complete obvious numbers. After 8 numbers have been completed in any row, box or column, the remaining number is obvious. Be sure to write in that number immediately. It may help you see the solution to another cell.
6) Stuck? Go through the numbers, 1 to 9. Start with 1 and systematically scan the puzzle looking for obvious (or not so obvious) places where another 1 could go. Sometimes when you are stuck, it means that you have made an error. Ask a friend to check the solution to make sure all the entries you have made so far are correct.
Intermediate and Advanced Techniques
Perhaps the easiest way to learn intermediate and advanced sudoku puzzle-solving techniques is with the aid of videos. Two videos you may want to check out are Double Scanning Technique and Wayne Gould‘s X-Wing Strategy.