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Read before your next round of Diagonal Sudoku

A small practice goal

Watch the feedback after an action. A message can explain whether the input was accepted or whether a rule needs attention. Refer to the controls when needed.

The goal to keep in mind

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. Keep that objective in view throughout the round. Start with a deliberate move.

A walkthrough of the rules

  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.

Getting comfortable with 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. Use the control method described here for this activity. Read the example below alongside these instructions.

A useful example

On one puzzle in this collection, row 1, column 1 has 1 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. Keep the controls nearby.

A mistake to avoid

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. Choose one rule to keep in mind for this round. Apply it consistently rather than guessing what another version might allow.

Game-specific help

While reading the Guide, what is the goal of Diagonal Sudoku?

For clarity: 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.

Before I begin, what example helps explain Diagonal Sudoku?

The key detail is this: On one puzzle in this collection, row 1, column 3 has 3 in its solution. Read the clues on your current board before using that value; another puzzle can need a different entry.

While learning, 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.

For my first round, 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.

For my first round, 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.

For this browser game, where should I start with Diagonal Sudoku?

The key detail is this: Select an empty cell. The original clues cannot be edited.

When I return, 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.

Before I begin, how can I find Diagonal Sudoku again?

Here is the relevant explanation: Use the Games list or save this game page in your browser bookmarks. The Guide is linked from the playing page.

While reading the Guide, 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.