Classic 9x9 puzzle

Sudoku

Choose a difficulty and fill the board. Every row, column and 3x3 box must contain the numbers 1 through 9.

How to play Sudoku

Sudoku is a classic logic puzzle. Fill every empty cell so each row, column and 3x3 box contains the numbers 1 through 9 exactly once. Use notes to mark candidates and switch difficulty whenever you want a different challenge.