How to Play Classic Sudoku

THE PLAYBOOK · ACSIWANG

How to play Classic Sudoku

Choose a round of Classic Sudoku and settle into its rules. Fill all cells with 1–9; do not repeat a symbol in any row, column or region. Use the example below to understand a decision. Check the rule that explains your first action. Choose a clear next step rather than rushing through the instructions.

Review a difficult moment

When a decision goes wrong, compare it with the common mistake described below. Start again only when you intend to leave the current round. Use the example to check your reasoning.

Your goal

Fill all cells with 1–9; do not repeat a symbol in any row, column or region. An attractive position is not enough unless the goal is met. Check the rules when you are unsure.

Step by step

1. Select an empty cell. The original clues cannot be edited.
2. Choose a symbol from the number pad, or type it on a keyboard.
3. Turn Notes on to record candidate symbols without committing an answer.
4. Use Check entries to check your filled values. Hint reveals one value from the verified solution.
5. Complete the board, or choose New puzzle for another board.

Controls

Tap or click a cell and use the number pad. Keyboard: arrows select cells; digits (and A–G on 16×16) enter values; Backspace erases. Keep the playing area visible while using these controls. Avoid pressing the same control repeatedly while a move is being processed.

A useful example

Before filling a cell, compare the symbols already used in its row, column and 3 × 3 region. A candidate must be absent from all three. Apply the same reasoning to the position in your own round. Take a moment to compare.

Watch out for this

Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Compare the situation with the worked example. Compare the worked example with your own position. Use the reasoning, not an answer copied from a different board.

Common questions