A program for Android, by Fassor.

If you want to solve logic puzzles and train your mind as well, this is perfect for you! Sudoku is a free application for Android that brings you the classic puzzle game, Sudoku. In this game, there’s unlimited playtime, and you can even choose the difficulty of the level you wish to play (Easy to Very Hard). 

This Sudoku app is optimized for smartphones and tablets, and it also works offline so you can play it anytime and anywhere you want. In addition, it comes with beautiful graphics and a user-friendly interface, which makes the game even more fun and easy to play.