Expert Sudoku
Free expert Sudoku — the toughest tier, with minimal givens and deep deductions. Still always uniquely solvable by logic.
▶ Play Expert SudokuNo ads · no account · works offline
How to play Sudoku
Fill the 9×9 grid so every row, every column, and every 3×3 box contains the digits 1–9 exactly once. Tap a cell, then a number — or use Notes to pencil in candidates. There’s no guessing: every QZBrain puzzle is solvable by logic.
Frequently asked questions
Are expert puzzles solvable without guessing?
Yes. They demand advanced techniques and concentration, but every puzzle has a single solution reachable by logic.
Is it free?
Yes — completely free, with no ads and no sign-up.
Do I need an account or an internet connection?
No account, ever. Once loaded it works fully offline; your progress stays on your device.
Enjoy the focus? QZBrain turns it into a calm daily habit — adaptive training for memory, attention, and speed. Free on web, iPhone, and Android. Or read more articles on brain training.