Sudoku Challenges is a logic-based, combinatorial number-placement puzzle. 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" or "blocks") contain all of the digits from 1 to 9. Each puzzle will start at a partially completed grid, which has a single solution. - Two themes / modes: Day (Light) and Night (Dark) - Statistics of scores / progress - Global leaderboard - Daily challenges to earn bonus score and hints - Four difficulties: Easy, Medium, Hard, and Master. Tap a cell to select it. Tap a digit at the bottom row to fill it into the selected cell. Use eraser to clear the current cell. Tap the Note button to turn on the draft mode. Use hints wisely to reveal any cells.