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 Web-based apps. The best Sudoku alternative is Sudoku Ninja, which is free. Other Sudoku like games are LibreSudoku, Sudoku Master, Sudoku Challenge and Sudoku & Variants.