THE PLAYBOOK · W3CHACK
How to play Diagonal Sudoku
Diagonal Sudoku gives you a focused activity to play in your browser. Fill all cells with 1–9; do not repeat a symbol in any row, column or region. The two long diagonals must also contain each symbol once. Look at what changes after your first action. Read the objective before making your first input. Choose a clear next step rather than rushing through the instructions.
A careful first round
Before your first action, say what you are trying to achieve. Then compare the result with the goal. Make the next step deliberately.
Your goal
Fill all cells with 1–9; do not repeat a symbol in any row, column or region. The two long diagonals must also contain each symbol once. An attractive position is not enough unless the goal is met. Try to explain the aim in your own words.
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. Read a button’s label before selecting it. Look at the feedback after the action.
A useful example
On one puzzle in this collection, row 1, column 1 has 5 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. Keep the controls nearby.
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. After a move, check what changed. Decide which rule explains the new state before acting again.
Common questions
For a quick reminder, what is the goal of Diagonal Sudoku?
Here is the relevant explanation: Fill all cells with 1–9; do not repeat a symbol in any row, column or region. The two long diagonals must also contain each symbol once.
While learning, how do I control Diagonal 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 my first round, what example helps explain Diagonal Sudoku?
Keep this in mind: On one puzzle in this collection, row 1, column 1 has 2 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 Diagonal Sudoku?
For clarity: Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
What format does Diagonal Sudoku offer?
The key detail is this: Play using the solo mode shown on this page. Read the controls before starting a new round.
While reading the Guide, which play mode does Diagonal Sudoku use?
The mode on this page is Solo. Same-device play uses one screen; this game library does not provide internet matchmaking.