Classic Sudoku — printable PDFs

The original number puzzle. Fill the 9×9 grid so every row, column, and 3×3 box contains each digit from 1 to 9 exactly once. Classic Sudoku is pure deductive logic — no arithmetic, no extra rules, just the constraints of a Latin square with the bonus box constraint. It rewards systematic scanning: pick a row, see which digits it's missing, eliminate the ones that can't fit into each open cell.

Rules: every row, column, and 3×3 box must contain the digits 1–9 with no repeats. Start by looking for hidden singles — cells where only one digit can legally go. When those run out, move to naked pairs, then pointing pairs, then the harder techniques.

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