Game guide · CTCPX
Learn the rules of Classic Sudoku
Read the aim of Classic Sudoku, then make your first move. Fill all cells with 1–9; do not repeat a symbol in any row, column or region. Check the relevant rule before repeating a move. Check the rule that explains your first action. Check the relevant rule before repeating a move.
Build familiarity through play
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. Return to the instructions when a step is unclear.
Work through the instructions
- 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.
Making selections and moves
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. Contact us with the game and device if a control does not respond.
A closer look at one example
On one puzzle in this collection, row 1, column 2 has 3 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. Check the stated objective.
One detail worth checking
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Check the rule before repeating the action. Read one step at a time and try it on the playing area. Match the instruction to the control you use.
Questions about this game
What is the goal of Classic Sudoku?
For clarity: 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?
For clarity: 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 my first round, what example helps explain Classic Sudoku?
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.
For this browser game, what should I watch out for in Classic Sudoku?
Here is the relevant explanation: Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
What format does Classic Sudoku offer?
Keep this in mind: 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.
For this browser game, where should I start with Classic Sudoku?
The key detail is this: Select an empty cell. The original clues cannot be edited.
While learning, do I need an account or a payment for Classic Sudoku?
The key detail is this: No player account or payment is needed. Game scores are recreational results, not cash prizes.
For this browser game, 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.
As a new player, how do I report an issue with Classic Sudoku?
For clarity: 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.
