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About hard puzzles
Hard puzzles start with 24–32 digits and need at least one pair or triple: two squares in a row that can only hold the same two digits, for example, which means no other square in that row can hold them. They never need anything harder, and they never need a guess.
Press New puzzle for another one at this level. Every puzzle has exactly one solution.
All five levels
| Level | Digits given | What it takes |
|---|---|---|
| Easy | 36–40 | Only naked and hidden singles |
| Medium | 28–34 | At least one pointing pair or box/line reduction; nothing harder |
| Hard | 24–32 | At least one naked or hidden pair or triple; nothing harder |
| Expert | 24–30 | One or two X-Wing or XY-Wing steps |
| Evil | 24–26 | A Swordfish, or three or more X-Wing / XY-Wing steps |
Questions
What technique does a hard puzzle need?
At least one naked or hidden pair or triple. Our solver tries every simpler move first and only rates a puzzle hard when it has to use one.
I am stuck. Should I guess?
No. Every puzzle here can be finished by logic. Fill in notes for the whole row, column or box you are looking at and look for two squares with the same two options. Or tap Hint: it names the technique it used.
Is this the hardest level?
No. Expert and evil go further, with X-Wings, XY-Wings and Swordfish.