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Printable hard Sudoku puzzles
Around 30 givens, built so the easy deductions run out early. These are the boards where you spend more of the solve ruling digits out than writing them in — print one or two per page.
Difficulty
Puzzles per page
Pages — 2 puzzles
Paper size
Answer key
Sheet title
Choose “Save as PDF” as the destination in the print dialog to keep a copy. Answers print on their own sheet at the end, so you can hand out the puzzles without them.
Why hard boards print badly at four per page
On a hard board you will be carrying five or six candidates in some cells, and a grid printed four to a page does not have the room. It is the one difficulty where paper is genuinely worse than a screen, and the way to close that gap is to give each board a whole page or half of one.
Some solvers print two copies of the same sheet for this reason — one to mark up freely and one clean to write the final answer into.
They are all solvable without guessing
A hard board being hard is not the same as it being ambiguous. Every puzzle here is carved to exactly one solution, so a complete chain of deductions always exists, and the moment you are considering a coin flip you have missed something rather than found the limit of the puzzle. Usually it is a pointing pair or an X-Wing.
Nothing is uploaded, and there is nothing to sign up for
The puzzles are generated in your browser the moment you open the page, and printing uses your own print dialog. There is no download endpoint, no email wall and no watermark. Hit New sheet as many times as you want — every press is a different set of boards.
Every puzzle has exactly one solution
Cells are removed one at a time and any removal that would leave the grid with two valid answers is put back. That matters more on paper than on screen: there is no undo on a printed sheet, so a puzzle that turns out to have two answers wastes the whole solve. The answer key on the second page is the real solution, not one of several.
Frequently asked questions
How hard are these printable hard Sudoku puzzles?
Around 30 givens, and built so the easy deductions run out early. Expect to spend more of the solve ruling digits out than writing them in, and expect fifteen to thirty minutes per board.
Why not print four hard puzzles to a page?
Because on a hard board you will be carrying five or six candidates in some cells, and a grid printed four to a page has no room for them. One or two per page is the only layout that works.
Do hard Sudoku puzzles ever require guessing?
No. Every board here is carved to exactly one solution, so a complete chain of deductions always exists. If you are considering a coin flip, a technique is missing — usually a pointing pair or an X-Wing.
Are the answers included?
Yes, on a separate sheet printed after the puzzles.
Keep reading
Or play without the printer
The same generator runs a full board in your browser, and Action Sudoku puts a real opponent on it. Free on iOS and Android.