Sudoku is a popular number-placement puzzle game that originated in Japan. The objective of Sudoku is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids (called “regions” or “boxes”) contains all of the digits from 1 to 9. The puzzle starts with some cells already filled in with numbers, and the player’s task is to use logic and deductive reasoning to fill in the remaining cells.

The rules are simple:

1. Each row must contain all the numbers from 1 to 9 with no repetition.
2. Each column must contain all the numbers from 1 to 9 with no repetition.
3. Each 3×3 subgrid must contain all the numbers from 1 to 9 with no repetition.

Sudoku puzzles come in various difficulty levels, ranging from easy to very challenging. The level of difficulty is determined by the initial arrangement of numbers and the complexity of the logical steps required to solve the puzzle. Sudoku has gained widespread popularity as a brain-teasing and enjoyable pastime, appearing in newspapers, puzzle books, and online platforms.