A free program for Android, by Kusya.
Sudoku - Happy Brain is an educational game that can help you improve your logical thinking skills. It is a logic-based puzzle game where you have to put numbers from 1 to 9 in a 9×9 grid so that each column, each row, and each of the nine 3×3 subgrids that compose the grid contain all of the numbers from 1 to 9.
This game can be played with either one or two players. You can also play with your friends or family.
It is a logic game, so you need to use your brain to solve it. You can use the hints and help to solve the puzzles.
Sudoku - Happy Brain is free to play, but you can also buy in-game items with real money.
