Printable
Very hard printable Sudoku
The expert level: about 25 givens, close to as few as a uniquely solvable puzzle usually allows. Roughly one in three needs techniques beyond singles.
Free to copy: schools, libraries, care homes and clubs may reproduce and hand out these sheets at no cost.
How few givens can there be?
Mathematically, a Sudoku with exactly one solution needs at least 17 givens. Such grids are rare and very hard to generate; most expert puzzles in newspapers have between 22 and 26. Ours sit around 25.
What you'll need
At expert level you'll rarely get through without full candidate lists. After that it's about spotting patterns: naked and hidden pairs, pointing pairs between a box and a line, and in the toughest grids an X-Wing.
About a third of these puzzles can't be solved with singles alone. The rest can – but only if you don't miss a single one.
For a puzzle night
One expert puzzle per page in large print leaves the most room for notes. If you like a contest, print the same sheet twice and write your times in the field above the puzzle.
By difficulty: Daily puzzle· Mixed· Easy· Medium· Hard· Expert
More: Kids’ Sudoku· Blank grid· 4 per page· 6 per page
Rules · Techniques · Play