Game guide · LYLIANYING
Learn the rules of Diagonal Sudoku
Open Diagonal Sudoku, check the instructions and begin a round. 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. Choose a clear next step rather than rushing through the instructions.
Take a closer look while playing
After a move, check what changed. Decide which rule explains the new state before acting again. Refer to the controls when needed.
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. Read that aim before choosing your first action. Try to explain the aim in your own words.
Follow these playing steps
- 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.
The controls to know
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. Return to the rules if the result is unexpected.
Work through an 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. Choose a deliberate next step.
A useful caution
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Read the feedback to see why an action did not have the expected result. After a move, check what changed. Decide which rule explains the new state before acting again.
Helpful answers for players
Before I begin, what is the goal of Diagonal Sudoku?
Keep this 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.
As a new player, 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.
What example helps explain Diagonal Sudoku?
For clarity: 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.
When I return, 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 a quick reminder, 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.
When I return, 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.
For my first round, 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?
Here is the relevant explanation: No player account or payment is needed. Game scores are recreational results, not cash prizes.
For a quick reminder, how can I find Diagonal Sudoku again?
For clarity: Use the Games list or save this game page in your browser bookmarks. The Guide is linked from the playing page.
When I return, how do I report an issue with Diagonal Sudoku?
The key detail is this: 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.
