Hard printable sudoku

Sudoku with few starting numbers that you cannot finish with singles alone. You need patience, pencil marks and some technique: pairs, locked candidates and, in the toughest spots, patterns like the X-Wing.

Every puzzle has a unique solution, checked by the program that generated it: no guessing, logic gets you to the end. The solution is on page 2 of the PDF and, on screen, below the grid, hidden until you open it.

If you get stuck, the technique guides explain what to look for. The difficulty rating is an estimate: some puzzles will feel harder than others.

The puzzles

• Hard Sudoku #1hard · 24 clues
• Hard Sudoku #2hard · 28 clues
• Hard Sudoku #3hard · 27 clues
• Hard Sudoku #4hard · 27 clues

Useful techniques

• Locked candidates
• Hidden pair
• X-Wing
• XY-Wing

Want several puzzles on one page? The printable sudoku generator builds an A4 sheet with several puzzles, the rules and the answers (the page opens in Italian; pick English from its language menu).