Smart Sudoku

Choose a difficulty or start the Daily Challenge to begin a new grid. Fill each cell with numbers 1 to 9 so every row, column, and 3x3 box contains all digits without repeats. Use pencil marks to note possible candidates and let auto candidates update as the board changes. Tap Smart Hint to see step by step logic that explains why a move works, not just the answer. Toggle error check to highlight conflicts, and use undo and redo to refine your strategy safely. Finish the puzzle to earn stats and streak progress, then increase the difficulty for a tougher test.