Pure-sudoku

Classic 9x9 Sudoku, ad - free! It supports step - by - step hints, one - click marking of all candidate numbers, independent marking and drawing. There are multiple difficulty levels of questions built - in: Easy/Normal/Medium/Difficult/Expert/Extreme, with 1000 questions for each level. It can be played offline, and 17 - clue Sudoku puzzles are also integrated. Sudoku Rules: Fill in the 9x9 grid with numbers 1~9 such that each row, column, and 3x3 box contains each number exactly once.