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Diagonal Sudoku: a guide for your next round

Something to practise

Read one step at a time and try it on the playing area. Match the instruction to the control you use. Notice the feedback after each input.

Your objective

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. The feedback beside the game helps you follow the round. Check the rules when you are unsure.

How to proceed

  1. Select an empty cell. The original clues cannot be edited.
  2. Choose a symbol from the number pad, or type it on a keyboard.
  3. Turn Notes on to record candidate symbols without committing an answer.
  4. Use Check entries to check your filled values. Hint reveals one value from the verified solution.
  5. Complete the board, or choose New puzzle for another board.

Keyboard and screen 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. Use the control method described here for this activity. Read the example below alongside these instructions.

Learn from a sample situation

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.

A common point of confusion

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. Compare the worked example with your own position. Use the reasoning, not an answer copied from a different board.

Read these answers for extra help

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.

When I return, how do I control Diagonal Sudoku?

Keep this in mind: 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 Diagonal Sudoku?

The key detail is this: On one puzzle in this collection, row 1, column 2 has 2 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry.

For my first round, what should I watch out for in Diagonal Sudoku?

Keep this in mind: 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 Diagonal Sudoku offer?

Play using the solo mode shown on this page. Read the controls before starting a new round.

On this playing page, 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.

On this playing page, where should I start with Diagonal Sudoku?

For clarity: Select an empty cell. The original clues cannot be edited.

Do I need an account or a payment for Diagonal Sudoku?

No player account or payment is needed. Game scores are recreational results, not cash prizes.

For my first round, how can I find Diagonal Sudoku again?

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.