Sudoku is a well-known puzzle based on logical placement of numbers. how to play the goal is to place numbers from 1 to 9 in each of the empty cells in a grid of 9x9, consisting of 3x3 subgrades called regions. the puzzle contains some initial clues, which are numbers inserted into some cells, so as to allow for induction or deduction of numbers in cells that are empty. each column, row, and region can only have a number from 1 to 9 each. solving the problem requires only logical reasoning and some time. features this sudoku puzzle has different levels of difficulty. to each game completed successfully in sudoku 9x9 the player earns points: ○ easy (+1) ○ normal (+5) ○ hard (+10) ○ very hard (+20) sudoku puzzle contains access to player game statistics, such as game time, and quantities of times that the game ended as the difficulties occur. the app has a beautiful and clean design, focused on the comfort and gameplay of the player.