THE PLAYBOOK · IHAHOOO
How to play Diagonal Sudoku
Take a moment with Diagonal Sudoku before moving to another game. 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. Check the relevant rule before repeating a move. Choose a comfortable screen position before beginning. 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. Keep the objective visible.
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. Keep that objective in view throughout the round. Return to the instructions when a step is unclear.
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. On a smaller screen, keep the active part of the board within view. Use the visible help when you are unsure of the next input.
A useful example
On one puzzle in this collection, row 1, column 1 has 3 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. Read the matching step again.
Watch out for this
Notes are reminders, not final entries. A full board only counts as complete when it satisfies every rule. Check the rule before repeating the action. Locate the buttons and input area before beginning a long round. Use the on-screen labels to avoid an accidental restart.
Common questions
For a quick reminder, 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.
On this playing page, how do I control Diagonal Sudoku?
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?
Keep this in mind: 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.
While learning, what should I watch out for in Diagonal Sudoku?
Here is the relevant explanation: 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?
For clarity: Play using the solo mode shown on this page. Read the controls before starting a new round.
As a new player, which play mode does Diagonal Sudoku use?
For clarity: The mode on this page is Solo. Same-device play uses one screen; this game library does not provide internet matchmaking.