## Sudoku Rules

Sudoku, a puzzle game originating from Japan, has become one of the most popular logic puzzles worldwide. It's not just a pastime but an excellent way to exercise your brain. The charm of Sudoku lies in its **simple rules and deep strategy**. The game is played on a 9x9 grid, with the goal of filling each empty cell so that:

- Every row contains all numbers from 1 to 9, without repetition
- Every column contains all numbers from 1 to 9, without repetition
- Every 3x3 sub-grid contains all numbers from 1 to 9, without repetition

Although based on numbers, **Sudoku doesn't require complex mathematical calculations**. It tests your **logical thinking and concentration**.

## Sudoku Playing Techniques

The Sudoku on this page can be played directly in your browser, without the need to download any application, allowing you to enjoy Sudoku anytime, anywhere. You can choose different difficulty levels, from beginner to expert. This page also provides a hint feature; you can click the hint button to get assistance.

![Sudoku Solving Hint](https://slefboot-1251736664.file.myqcloud.com/20241011_ai_gallery_sudoku_case1.png)

Additionally, there's an undo feature supporting up to 3 steps of undo. Here are some Sudoku playing strategies:

- Observe the initial layout: At the start of the game, some cells are already filled with numbers.
- Analyze empty spaces: Use existing numbers to deduce possible options for empty cells.
- Fill step by step: Start with the most certain cells and gradually complete the entire grid.
- Check for conflicts: Ensure that the numbers you enter don't conflict with those in the same row, column, or 3x3 sub-grid.
- Repeated reasoning: As the grid fills up, new clues will constantly emerge, helping you solve more puzzles.

Some advanced techniques:

1. Elimination method: Focus on cells with fewer options. By eliminating impossible numbers, you can often find the only correct answer.
2. Candidate notation: Mark all possible numbers in empty cells. This method can help you quickly locate the correct answer in later stages.
3. Block analysis: Divide the 9x9 grid into three 3x3 large blocks. Analyzing the relationships between these blocks often reveals new breakthroughs.
4. "Sole candidate" method: If a number has only one possible position in a row, column, or 3x3 sub-grid, it must be placed there.

## Benefits of Sudoku

Playing Sudoku is not just a pastime; it brings many benefits:

1. Improves concentration: Requires sustained attention to solve puzzles.
2. Enhances logical thinking: Trains your brain for systematic thinking.
3. Reduces stress: Immersing yourself in puzzle-solving can temporarily relieve worries.
4. Prevents cognitive decline: Regular mental exercise helps maintain brain vitality.
5. Sense of achievement: The satisfaction of solving a difficult puzzle is unparalleled.
