Print sudoku — hard
Hard sudokus give away only a few starting numbers: real thinking is required here. Feel free to print the solutions sheet too — peeking is allowed, it's your puzzle. These puzzles are also guaranteed to be solvable without guessing.
Frequently asked questions — hard level
How many starting numbers does a hard sudoku have?
Only 27 of the 81 squares are filled in. There's little to hold on to, and you'll often need several reasoning steps before you can place a number with certainty.
Do I have to guess on a hard sudoku?
No, never. Even our hardest puzzles have exactly one solution that can be found with pure logic. A handy paper trick: jot small candidate numbers in the corner of empty squares.
What if I'm completely stuck?
Print the solutions sheet and look up just one square — the given numbers are printed in bold, so you can see exactly what was provided. Often one number is enough to get going again.
Another level, or rather play online?
Not sure about your level? Start easy and build up. On the print sudoku overview page you can read more about the PDFs, and in the rules you'll find all the starter tips in plain language.