Game guide · CTCPX
Understand the basics of Diagonal Sudoku
Choose a round of Diagonal Sudoku and settle into its rules. 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. Choose a clear next step rather than rushing through the instructions. Identify the playing area and the controls you need. Use the example below to understand a decision.
A small practice goal
Compare the worked example with your own position. Use the reasoning, not an answer copied from a different board. Refer to the controls when needed.
What counts as success
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. Use the instructions to see which actions move you towards it. Check the rules when you are unsure.
Making your moves
- 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.
How to use the 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. Read the example below alongside these instructions.
Follow the example
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. Compare this with the rule that governs the move. Take a moment to compare.
Avoid this misunderstanding
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Take a moment to reassess the position before continuing. Before your first action, say what you are trying to achieve. Then compare the result with the goal.
Further help with the game
On this playing page, what is the goal of Diagonal Sudoku?
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 this browser game, what example helps explain Diagonal Sudoku?
The key detail is this: 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. The two long diagonals must also contain each symbol once.
For my first round, what should I watch out for in Diagonal Sudoku?
The key detail is this: Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule.
Before I begin, what format does Diagonal Sudoku offer?
Play using the solo mode shown on this page. Read the controls before starting a new round.
Before I begin, which play mode does Diagonal 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.
As a new player, where should I start with Diagonal Sudoku?
Select an empty cell. The original clues cannot be edited.
For a quick reminder, do I need an account or a payment for Diagonal Sudoku?
For clarity: No player account or payment is needed. Game scores are recreational results, not cash prizes.
While learning, how can I find Diagonal Sudoku again?
Keep this in mind: Use the Games list or save this game page in your browser bookmarks. The Guide is linked from the playing page.
While learning, how do I report an issue with Diagonal 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.
