Sudoku is a popular logic-based number puzzle game that originated in Japan. The objective of the game is to fill a 9x9 grid with numbers 1 to 9 such that each row, column, and 3x3 sub-grid contains all the numbers 1 to 9 without repetition. The puzzle starts with some numbers already filled in and the player has to use logic and deduction to fill in the rest of the grid. The game is considered a mental workout and is enjoyed by people of all ages. Despite its simplicity, Sudoku can be challenging and engaging, making it a popular pastime for puzzle enthusiasts all over the world.