A free app for Android, by TikTik Game.

Welcome to Classic Sudoku – puzzle brain, one of the best free games of the Sudoku family. It is also one of the best Sudoku games for beginners. You can learn to play Sudoku in a very easy and simple way. The difficulty of the game depends on you. If you’re a beginner, it’s best to start with the easy levels. As you become a pro, you can move to the more difficult levels. There are four levels of difficulty: Easy, Medium, Hard and Expert. You can customize the board and the theme of the game. The board has nine 3×3 grids, and each grid contains numbers from 1 to 9. There are no repeated numbers in each grid. The objective of the game is to place the numbers from 1 to 9 in the grids, so that every number only appears once in each row, each column, and each 3×3 grid.