THE PLAYBOOK · IHAHOOO
How to play Classic Sudoku
Take a moment with Classic Sudoku before moving to another game. Fill all cells with 1–9; do not repeat a symbol in any row, column or region. Keep the game area visible while you use its controls. Identify the playing area and the controls you need. Keep the game area visible while you use its controls.
Make the controls familiar
Locate the buttons and input area before beginning a long round. Use the on-screen labels to avoid an accidental restart. Notice the feedback after each input.
Your goal
Fill all cells with 1–9; do not repeat a symbol in any row, column or region. The feedback beside the game helps you follow the round. Return to the instructions when a step is unclear.
Step by step
- Select an empty cell. The original clues cannot be edited.
- Choose a symbol from the number pad, or type it on a keyboard.
- Turn Notes on to record candidate symbols without committing an answer.
- Use Check entries to check your filled values. Hint reveals one value from the verified solution.
- 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. On a smaller screen, keep the active part of the board within view. Make sure you are interacting with the game rather than the surrounding page.
A useful example
On one puzzle in this collection, row 1, column 1 has 8 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry. Use the example as a guide rather than a substitute for reading your board. Verify the rule before continuing.
Watch out for this
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Read the feedback to see why an action did not have the expected result. When a decision goes wrong, compare it with the common mistake described below. Start again only when you intend to leave the current round.
Common questions
When I return, what is the goal of Classic Sudoku?
Fill all cells with 1–9; do not repeat a symbol in any row, column or region.
While learning, how do I control Classic Sudoku?
The key detail is this: 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.
For this browser game, what example helps explain Classic Sudoku?
The key detail is this: On one puzzle in this collection, row 1, column 1 has 9 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry.
While learning, what should I watch out for in Classic Sudoku?
Keep this in mind: Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
What format does Classic Sudoku offer?
Play using the solo mode shown on this page. Read the controls before starting a new round.
As a new player, which play mode does Classic Sudoku use?
Keep this in mind: The mode on this page is Solo. Same-device play uses one screen; this game library does not provide internet matchmaking.