Fill the grid so each row contains the numbers 1 through 9
Fill the grid so each column contains the numbers 1 through 9
Fill each 3×3 box so it contains the numbers 1 through 9
Do not repeat any number in a row
Do not repeat any number in a column
Do not repeat any number in a 3×3 box
Use the given numbers as fixed clues
Place numbers only where they fit all rules
Continue until every empty cell is filled correctly