Sudoku Classic | Play Online
One of the most popular logic puzzles. Fill a 9×9 grid with digits so that every row, every column and each 3×3 box contains all numbers from 1 to 9.
If the game does not start, click the button to open it in a new tab.
About Sudoku Classic
Sudoku Classic is a clean and relaxing number puzzle. The challenge is to complete the grid without repeating digits in any row, column or 3×3 box. You can add pencil notes, use hints if the mode allows and try to solve with the fewest mistakes and the best time.
How to Play
- Select an empty cell and enter a digit from 1 to 9.
- A valid board has no duplicate numbers in any row, column or 3×3 box.
- Use pencil notes to mark candidates for a cell. Replace notes with a final digit when you are sure.
- Use undo, redo and eraser as needed. Hints can reveal a move if the game provides them.
- Finish when all cells are filled and all rules are satisfied.
Features
- Free to play in the browser. No download required.
- Responsive layout that works on phones, tablets and desktops.
- Pencil notes, undo and hints to support different play styles.
- Multiple difficulties or boards depending on the provider.
Tips and Strategies
- Start with singles. Rows or columns with eight filled cells often have one obvious number left.
- Scan boxes using cross hatching. Look across rows and columns to see where a digit can fit.
- Look for hidden singles and naked pairs to remove candidates.
- Keep notes clean. Remove candidates as soon as they become impossible.
- Avoid guessing early. If stuck, review each box and try a different area.
Controls
- Mobile: tap a cell then tap a number. Toggle pencil mode for notes and use eraser or undo if available.
- Desktop: click a cell then click a number on the pad or press keys 1 to 9. Use on screen buttons for notes, undo and hints.
FAQ
Q: Is this game free
A: Yes. It runs free in your browser.
Q: Do I need to download anything
A: No. Open the page and start playing.
Q: Does it work on mobile and PC
A: Yes. The page and embed are fully responsive.
Q: I see a black screen. What can I try
A: Refresh the page, disable ad blockers or extensions, or use the Open Game button above.
Q: What are pencil notes
A: Small candidate digits you use to track possible values for a cell. Replace them with a final number when certain.