Sudoku is game with goal of placing numbers 1 to 9 on missing spots in 9×9 fields grid. Each row, column and each of nine 3×3 subgrids should contain all numbers from 1 to 9. Sudoku is well know and popular puzzle game.
Just tap on an empty spot and select the desird number you like to fill in the spot. To change a number you have to tap on it and in the popup window select the "DEL"-button and enter the correct number.
This app support both the iPhone as well as the iPad with Retina (high resolution graphics).