🔢 This free printable sudoku prints on a single page. The answer key sits in a small strip at the bottom — fold it backward along the dotted line before you start, and you can solve honestly without ever seeing the solution. A real challenge — high-school level reasoning and vocabulary recommended.
| 1 | 6 | 5 | 3 | |||||
| 8 | 9 | 4 | ||||||
| 5 | 9 | 1 | ||||||
| 1 | 3 | 5 | ||||||
| 1 | 7 | |||||||
| 3 | 8 | 1 | ||||||
| 8 | 2 | 9 | ||||||
| 2 | 7 | 3 | ||||||
| 3 | 6 | 1 | 7 |
A Hard-rated grid usually has a handful of cells that resist simple scanning until you bring in a sharper technique. Here's where to focus:
These intermediate moves are usually enough to crack a Hard grid without guessing. For pairs, triples, and more advanced patterns, see our complete Sudoku strategy guide.
Hard Sudoku #1 starts you off with just 28 numbers, and the digit 4 appears only once among them. Straight scanning for singles gets you to roughly the halfway mark, and then the grid stalls. To get it moving again you'll need a pointing pair (a digit locked to one row or column inside a box) and then a naked or hidden pair. After that, singles carry you to the finish.
Row 1 needs a 9, and there are five empty cells to choose from. Column 3 is out because the top-left box already has a 9 (row 3). Columns 4 and 6 are out because the top-middle box already has one (row 2). Column 9 is out because there's a 9 lower down in that column (row 7). That leaves just one home: the 9 goes in row 1, column 7. Notice you found it by asking "where can this digit go?" instead of "what goes in this cell?" — that switch is the key to Hard grids.