Sudoku solving techniques

Sudoku solving strategies are a kind of algorithm for solving Sudoku puzzles. Sudoku tactics help solve Sudoku puzzles faster and find a way out of complex puzzles.

Knowing one or more Sudoku solving strategies makes it very difficult to solve puzzles quickly and effectively. It's optimal to know and be able to apply at least 10 Sudoku techniques.

As of 2024, there are at least 14 basic techniques for solving Sudoku puzzles in this category. Among these strategies, you can find algorithms for solving simple Sudokus as well as complex Sudoku strategies. In our articles, you'll find explanations and examples of how Sudoku strategies work. 

Algorithm for solving Sudoku

There isn't a single correct algorithm for solving Sudoku because there are different methods for solving Sudoku, and the order of their application in practice can vary. Below is one of the algorithms used by the author of this text:

• The first step - cross-hatching technique Sudoku. At the initial stage, we look for the simplest large numbers that can be immediately set.
• The second step - pencil markings. A very important stage in solving Sudoku, where we work with candidates and look for "weak cells."
• The third step - using Sudoku extreme techniques, such as fish strategies. Complex techniques help find a way out even in the most difficult situations and turn devilish Sudoku into elementary Sudoku.

There is another algorithm for solving complex Sudokus:

• The first step - fill in all the candidates for all empty cells.
• The second step - look for lone candidates and apply strategies related to them.
• The third step - look for pairs and apply strategies for paired candidates.
• The fourth step - look for triplets and triple candidates and apply techniques for them.
• The fifth step - apply advanced strategies to find chains, X-wing, Y-wing, XY-wing.

Basic sudoku strategies

Easy trick to solve Sudoku is to apply basic Sudoku tactics. These tactics are easy to understand and apply in practice. With their help, you can solve beginner-level Sudoku and intermediate-level Sudoku, which is enough for 90% of Sudoku enthusiasts. Below is a list of basic Sudoku techniques:

1. Last free cell technique
2. Last remaining cell technique
3. Last possible number technique
4. Obvious singles technique
5. Obvious pairs technique
6. Obvious triples technique
7. Hidden singles technique
8. Hidden pairs technique
9. Hidden triples technique
10. Pointing pairs technique
11. Pointing triples techniques

Advanced sudoku methods

There are many complex Sudoku strategies. However, the main three expert strategies can be distinguished:

1. X Wing strategy
2. Y Wing strategy
3. SwordFish strategy

Of course, this is not an exhaustive list of strategies for solving complex Sudokus. But most advanced strategies are derivatives of these three tactics.