28-clue puzzles sit squarely in hard territory. Pencil marks are recommended, naked and hidden pairs are common, and most puzzles unlock through pointing pairs and box-line reduction.
53 empty cells. The 28-clue band consistently delivers a satisfying hard puzzle - challenging enough to demand pencil marks, friendly enough that you can usually finish in one sitting.
28-clue puzzles are where the satisfaction-to-time ratio peaks for many solvers. Hard enough to feel like a real workout, fast enough to fit into a coffee break, and always solvable with technique you can name and explain.
Pencil-mark the grid, then look for any digit that appears only once or twice in a unit - those are your immediate placements. Move to subset hunting: naked pairs in rows, columns, and boxes; hidden pairs where two digits collapse to the same two cells. Finally, scan box-row and box-column intersections for pointing pairs, which are the single highest-yield technique at this clue count.
For deeper coverage of the techniques you will need, see our guides on Pointing Pairs, Hidden Pairs, Naked Pairs, and the full Sudoku strategies hub.
This page is part of our Sudoku by clue count cluster. The fewer clues a puzzle has, the more advanced the techniques required. The proven minimum is 17 clues - see 17-clue Sudoku for the famous case. For the matching difficulty band see Hard Sudoku.
Two clues sounds like a small difference but it changes the candidate density meaningfully. 28-clue puzzles almost always require at least one subset elimination, while 30-clue puzzles often resolve through hidden singles alone. Expect a 28-clue puzzle to take roughly 50 percent longer than a 30-clue puzzle.
Strongly recommended. You can occasionally solve 28-clue puzzles by scanning, but pencil marks make subset patterns visible and turn a 25-minute solve into a 12-minute one.
A 28-clue Sudoku puzzle starts with 28 digits already placed in the grid out of 81 cells, leaving 53 cells for you to fill. Lower clue counts generally mean harder puzzles because you have less starting information.
Most experienced solvers complete a 28-clue puzzle in 12-22 minutes. Beginners may take significantly longer at this clue count, especially if pencil marks are required.
In our classification, 28-clue puzzles are rated hard. The exact difficulty also depends on which solving techniques are required - clue position matters as much as clue count.
Yes. Open any puzzle from this page and use the print function in your browser, or visit our printable collection at /printable-sudoku for printer-optimized layouts of hard puzzles.
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