This is the number one Sudoku app in Brain & Puzzle for a reason! You won’t be looking for a paper puzzle ever again!
Take a journey to feudal Japan with Sudoku Free. Beautiful graphics and killer features, this is the best Sudoku app available for iOS. Available for iPod, iPhone and iPad.

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 (also called "boxes", "blocks", "regions", or "sub-squares") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which typically has a unique solution.

Completed puzzles are always a type of Latin square with an additional constraint on the contents of individual regions. For example, the same single integer may not appear twice in the same 9×9 playing board row or column or in any of the nine 3×3 subregions of the 9×9 playing board.