The classic Sudoku puzzle is played on a 9×9 grid and follows these rules:

1. The grid is divided into nine 3×3 sub-grids, also known as “boxes” or “regions.”

2. Each row of the grid must contain the numbers 1 to 9, with no repetition of numbers within the row.

3. Each column of the grid must also contain the numbers 1 to 9, with no repetition of numbers within the column.

4. Each 3×3 sub-grid must contain the numbers 1 to 9, with no repetition of numbers within the sub-grid.

5. The puzzle starts with some numbers already filled in, known as “clues” or “givens.” These numbers are the starting point for solving the puzzle.

6. The goal of the puzzle is to fill in the remaining empty cells with numbers from 1 to 9, following the rules above, so that each row, column, and 3×3 sub-grid contains all the numbers 1 to 9 without any repetition.

7. There is only one solution to a valid Sudoku puzzle, and it can be achieved through logical deduction without any guessing or trial-and-error.

Sudoku is a fun and challenging puzzle game that requires careful thinking and problem-solving skills to solve.