Sudoku is described as 'Logic-based, combinatorial number-placement puzzle game. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid contains all of the digits from 1 to 9' and is a Puzzle Game in the games category. There are more than 50 games similar to Sudoku for a variety of platforms, including Android, iPad, iPhone, Android Tablet and Windows apps. The best Sudoku alternative is Sudoku Ninja, which is free. Other Sudoku like games are LibreSudoku, Sudoku Master, Sudoku Challenge and Sudoku & Variants.