Extreme Printable Sudoku
Extreme Sudoku sits at the very limit of logical solvability. With as few as 17 given digits — the mathematical minimum for a unique solution — every move requires deep chain logic and precise candidate tracking. Even world-class solvers may spend several sessions on a single puzzle.
Want to solve instead of print? Jump straight into a puzzle.
▶ Play Extreme Sudoku
Generate Extreme Puzzles
Given digits:
17–20
17–20
Avg. solve time:
2–4+ hours
2–4+ hours
Recommended age:
Any (elite)
Any (elite)
Techniques needed:
5 types
5 types
Who This Level Is For
Sudoku masters, solving marathons, the ultimate personal challenge.
Extreme is the absolute pinnacle of printed Sudoku difficulty. These puzzles sit at the mathematical edge of logical uniqueness. Only solvers with deep experience in forcing chains, ALS, and coloring should attempt them. A single puzzle can take multiple sessions.
Printing Tips for Extreme
- Print 1 per page at the largest possible size.
- Use graph paper alongside to track long forcing chains.
- Print the solution separately - You may need to verify specific steps.
- Select "Background graphics" in print settings for sharp borders.
- Print at 100% scale - Do not scale to fit.
Extreme Sudoku - Complete Guide
All Printable Levels - At a Glance
Techniques Required - Extreme
| # | Technique | Frequency |
|---|---|---|
| 1 | Forcing Chains | Every puzzle |
| 2 | ALS | Most puzzles |
| 3 | Coloring | Some puzzles |
| 4 | Bowman's Bingo | Occasionally |
| 5 | Nishio | Rarely |
How to Approach Extreme Puzzles on Paper
How difficult is Extreme? - Relative comparison
Paper vs. Online - Which is better for Extreme?
| Scenario | Paper | Online |
|---|---|---|
| Offline access (flights, rural) | ✓ Ideal | - |
| Track personal best times | Manual only | ✓ Automatic |
| Share with friends / classroom | ✓ Print copies | Share link |
| Undo mistakes | Eraser only | ✓ Unlimited undo |
| Hints when stuck | - | ✓ Cell reveal |
| Leaderboard & scoring | - | ✓ Only online |
Frequently asked questions
Are these puzzles unique? +
Yes. Every puzzle is generated fresh using a randomised backtracking algorithm. Each click of "Generate Puzzles" produces a new set that has never appeared on this site before.
Do extreme puzzles always have a unique solution? +
Yes. Our generator verifies that each puzzle has exactly one valid solution before serving it. You will never be forced to guess - Every step can be deduced logically.
Can I get solutions printed too? +
Solutions are not currently included on the printout. For classroom use, you can use our online solver to verify answers - Enter the given digits and hit Solve.
How do I play extreme online instead? +
Click below to play in your browser - Includes a timer, unlimited undo, notes mode, hints, and leaderboard scoring.
Play Extreme Sudoku Online
Get automatic timing, unlimited undo, mistake tracking, and leaderboard scores.