Game guide · GDFCWJ
Classic Sudoku: rules and examples
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. Look at what changes after your first action. Check the rule that explains your first action. Keep the game area visible while you use its controls.
Practice beyond the first move
Watch the feedback after an action. A message can explain whether the input was accepted or whether a rule needs attention. Make the next step deliberately.
Your goal
Fill all cells with 1–9; do not repeat a symbol in any row, column or region. Use the instructions to see which actions move you towards it. Try to explain the aim in your own words.
Start here and follow along
- 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.
The controls to know
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. A careful first action helps you become familiar with the layout. A new-round button replaces the current round.
A closer look at one example
On one puzzle in this collection, row 1, column 1 has 1 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry. Your next round may have a different position, so inspect it before acting. Look for the relevant detail.
Avoid this misunderstanding
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. A different version of the game may use a different rule. Choose one rule to keep in mind for this round. Apply it consistently rather than guessing what another version might allow.
A few questions answered
While learning, what is the goal of Classic Sudoku?
The key detail is this: Fill all cells with 1–9; do not repeat a symbol in any row, column or region.
As a new player, 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.
While learning, what example helps explain Classic Sudoku?
Keep this in mind: On one puzzle in this collection, row 1, column 1 has 1 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry.
On this playing page, what should I watch out for in Classic Sudoku?
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
On this playing page, what format does Classic Sudoku offer?
Play using the solo mode shown on this page. Read the controls before starting a new round.
While learning, which play mode does Classic Sudoku use?
The key detail is this: The mode on this page is Solo. Same-device play uses one screen; this game library does not provide internet matchmaking.
For this browser game, where should I start with Classic Sudoku?
For clarity: Select an empty cell. The original clues cannot be edited.
For this browser game, do I need an account or a payment for Classic Sudoku?
No player account or payment is needed. Game scores are recreational results, not cash prizes.
On this playing page, how can I find Classic Sudoku again?
Use the Games list or save this game page in your browser bookmarks. The Guide is linked from the playing page.
When I return, how do I report an issue with Classic Sudoku?
Keep this in mind: Use the contact form and include the game name, browser, device and the actions that led to the issue. Do not send passwords or payment details.