Play extreme Sudoku online
The premier class: extreme Sudoku starts with so few givens that even pairs and locked candidates eventually run out. This is where advanced patterns like X-Wing, XY-Wing and chains come in, along with patience and a clear head. At Sudoku Sagax they earn the most points when you solve them cleanly.
▶ Play a random Extreme Sudoku
What makes a Sudoku extreme
An extreme puzzle starts with around 28 givens, hardly fewer than a hard one. What makes it extreme is the way through, which runs through many small deductions. You will hit longer stretches without a new cell and work through the candidates step by step. Anyone who gets through here truly masters Sudoku.
The technique: X-Wing, XY-Wing, chains
- X-Wing. If a candidate appears in two rows only in the same two columns, it can be removed from the rest of those two columns (and vice versa with rows and columns swapped).
- XY-Wing (Y-Wing). Three cells with two candidates each, linked like a hinge, force the removal of a candidate in a fourth cell. A strong tool when nothing else bites.
- Chains. Chain cells in which a candidate has only two spots (strong and weak links). At the end of the chain a contradiction often shows and a candidate can be removed.
These patterns are demanding but learnable. Our techniques page explains them with examples.
Playing Extreme at Sudoku Sagax
The button above starts a random Extreme Sudoku right away, so you land in the game instead of a level grid. Every solved puzzle earns points for your fox rank and the leaderboard, and there is a shared daily challenge every day. Everything runs in the browser, ad-free, without trackers and without forced sign-up. A good Extreme puzzle takes around 35 minutes.
Other difficulty levels
Easy Sudoku · Medium Sudoku · Hard Sudoku
Printable Sudoku: four new puzzles every day from Easy to Extreme, with solutions.
Frequently asked questions
What is the difference between hard and extreme?
Extreme Sudoku has about as many givens as hard (around 28), but it can no longer be solved with pairs and locked candidates alone. It takes advanced patterns like X-Wing, XY-Wing or chains.
Are extreme Sudoku uniquely solvable?
Yes. Even the hardest puzzle at Sudoku Sagax has exactly one solution. The solution is verified on the server when you save it.