THE PLAYBOOK · 51XIONGFEI
How to play Classic Sudoku
Try Classic Sudoku at your own pace and keep its objective in view. 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. Treat the first round as a chance to learn the controls. Use the example below to understand a decision.
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. 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
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. Your next round may have a different position, so inspect it before acting. Keep the game’s format in mind.
Watch out for this
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. After a move, check what changed. Decide which rule explains the new state before acting again.
Common questions
Before I begin, what is the goal of Classic Sudoku?
Keep this in mind: 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?
Here is the relevant explanation: 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 a quick reminder, what example helps explain Classic Sudoku?
For clarity: 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.
What should I watch out for in Classic Sudoku?
The key detail is this: Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
For my first round, 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.
For this browser game, 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.
