🧠 Expert 9×9 Sudoku
Free online expert Sudoku puzzle — 22%% cells filled. No login required.
▶ Play Expert 9×9 Now — FreeAbout 9×9 Expert Sudoku
This is the classic 9×9 Sudoku grid with 22%% of cells pre-filled, leaving you with 78% to solve using pure logic. The 9×9 format consists of 81 cells arranged in 9 rows, 9 columns, and 9 sub-boxes — each must contain the numbers 1 through 9 exactly once.
At Expert difficulty, expect 60–120 minutes of deep logical work. This level is ideal for players who are experienced Sudoku solvers comfortable with intermediate techniques and ready for advanced methods.
Solving Strategies for Expert Difficulty
To solve expert 9×9 Sudoku efficiently, use these techniques in order:
- X-Wing: When a candidate appears in exactly two cells across two rows (same columns), eliminate it from those columns everywhere else.
- Swordfish: Extension of X-Wing across three rows and three columns.
- Hidden pairs: Two cells in a unit that exclusively contain two specific candidates — lock them in.
- Candidate elimination: After each placement, immediately update all affected pencil marks.
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Frequently Asked Questions
How many expert 9×9 puzzles are available?
Unlimited. Every time you click Play or New Game, a brand-new algorithmically generated puzzle is created. Our generator uses backtracking with MRV heuristic — you will never run out of unique puzzles.
Can I save my progress and resume later?
Yes. Your puzzle is auto-saved to your browser's localStorage every 15 seconds. Return within 24 hours on the same device and browser to resume exactly where you left off — including your pencil marks and timer.
Is this puzzle the same for everyone?
No — each puzzle is randomly generated uniquely for you. For a shared daily puzzle that's the same for everyone worldwide, visit the Daily Sudoku page.
Can I print this puzzle?
Yes. Visit the Printable Sudoku page to generate printable puzzles in any size and difficulty. 4 puzzles per page, save as PDF directly from your browser. No login needed.
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Free Expert 9×9 Sudoku — no login, no download, works on all devices.