Hard Sudoku
Play hard Sudoku free online, right here. These are challenging 9×9 puzzles — the entry rung of our difficulty ladder — free, in your browser, with no signup. Solve one, then climb toward expert and evil.
What is hard Sudoku?
Hard is a real step up from medium. The puzzle is still a standard 9×9 grid with the same rules — every row, column and 3×3 box holds 1 to 9 exactly once — but it offers far fewer easy placements. Once the obvious singles are gone, you have to start using intermediate techniques to make progress. That is what marks the difference between a casual puzzle and a genuinely difficult one.
On our ladder, hard is the gentlest tier we serve — a deliberate entry point before the bigger challenges. It is the natural place to build the habits that expert and evil puzzles demand.
Tips for solving hard Sudoku
A few habits make difficult Sudoku puzzles far more approachable. Pencil in your candidates first, then scan for the patterns below. We don’t re-teach strategy here — each technique links out to sudoku247wiki.com, where it’s explained step by step:
- Use notes. Mark every candidate in each empty cell before you commit to anything — hard boards reward bookkeeping.
- Scan for pairs. Two cells in a unit sharing the same two candidates lock those digits in place and clear them elsewhere.
- Work one technique at a time. Apply a single idea, update your notes, and look again — the board unwinds in steps.
Ready for a tougher challenge?
Hard is just the first rung. When these puzzles start to feel routine, step up — every tier above asks for a little more.
Print hard Sudoku
Prefer pencil and paper? Take a hard puzzle off-screen with our printable hard Sudoku page, or browse printable packs on our sister print site.
Hard Sudoku FAQ
What makes a Sudoku 'hard'?
A hard Sudoku gives up far fewer easy placements than an easy or medium one. After the obvious singles run out you have to lean on intermediate techniques — naked and hidden pairs, and pointing pairs — to keep cells falling. The rules never change: every row, column and 3×3 box still holds the digits 1 to 9 exactly once. It is the depth of logic, not unusual rules, that makes a puzzle hard.
How do I solve hard Sudoku?
Start by pencilling in candidates (notes) for every empty cell, then scan systematically. Look for naked and hidden pairs to eliminate options, and pointing pairs to clear candidates from a box-line. Work one technique at a time and the board opens up. Each technique name on this page links to sudoku247wiki.com, where it is explained step by step.
Is hard Sudoku harder than expert?
No — hard is the entry rung. Expert and evil are tougher tiers above it, needing more advanced techniques and several of them in combination. If hard feels comfortable, step up to expert; if it feels too brutal, it is still the gentlest difficulty we serve on this site.
Can I get hard Sudoku with answers?
Yes. Every puzzle we serve has a single, unique solution, so there is always exactly one correct answer to find. The board can check your entries and reveal the solution whenever you want to confirm you are on the right track.
Is hard Sudoku free to play?
Yes. Hard Sudoku is completely free and plays instantly in your browser — no download, no account and no paywall. Open the board above and start solving.