About 9×9 Extreme Sudoku
The classic 9×9 Sudoku — 81 cells, numbers 1–9, nine 3×3 boxes. The most played format worldwide.
At Extreme difficulty, 12% of the 81 cells are pre-filled, leaving 71 cells for you to solve. The hardest difficulty. Very few cells are pre-filled.
Tip: Use the Notes feature to pencil in candidates for each empty cell before committing.
Other difficulty levels for 9×9
Questions
How many extreme 9×9 Sudoku puzzles are available?
Unlimited. Every time you click "New Game" a brand-new algorithmically generated puzzle is created. You will never run out of puzzles.
Are these puzzles printable?
Yes! Visit our printable Sudoku page to generate 4 puzzles per page as a PDF. Free, no login needed.
What solving techniques does Extreme difficulty require?
All advanced techniques plus coloring and forcing chains.
Play Extreme 9×9 Sudoku now
Free, instant, no login — works on mobile, tablet and desktop.
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