Printable Hard Sudoku Puzzles

Six hard puzzles, verified by a solver to need exactly the techniques listed under each grid, with answer keys on a separate page. Prefer pencil marks and hints? Each puzzle is also playable online.

Hard #1 · 25 givens

Needs: Naked Single, Hidden Single, Naked Pair, Omission, Naked Triplet, Hidden Pair, Hidden TripletPlay online →

Hard #2 · 25 givens

Needs: Naked Single, Hidden Single, Naked Pair, Omission, Naked QuadPlay online →

Hard #3 · 24 givens

Needs: Naked Single, Hidden Single, Naked Pair, Omission, Hidden Pair, Hidden QuadPlay online →

Hard #4 · 25 givens

Needs: Naked Single, Hidden Single, Omission, Hidden Pair, Hidden TripletPlay online →

Hard #5 · 23 givens

Needs: Naked Single, Hidden Single, Naked Pair, Naked Triplet, Naked QuadPlay online →

Hard #6 · 24 givens

Needs: Naked Single, Hidden Single, Naked Pair, Omission, Hidden QuadPlay online →

Answer keys

Hard #1
Hard #2
Hard #3
Hard #4
Hard #5
Hard #6

Printable Hard Sudoku FAQ

How do I print these hard Sudoku puzzles?
Click the print button (or press Ctrl+P / Cmd+P) and use your browser's print dialog. Choose "Save as PDF" as the destination to download a PDF instead of printing on paper. The answer keys print on their own page so you can leave them out.
Are these printable hard puzzles really hard?
Yes, verifiably. Every puzzle is checked by a solver that records the exact techniques required, and these are rated Hard because of the hardest technique they need — not a guess or a star rating. Each puzzle lists its required techniques.
Can I play these puzzles online instead?
Every printable puzzle links to an online version with pencil marks, hints, and a timer — and the wider library has thousands more, organized by difficulty and by technique.