Medium sudoku
The step up from easy: you will need pencil marks and a few simple patterns.
Puzzle
| 5 | 3 | 2 | 4 | |||||
| 9 | 6 | |||||||
| 6 | 7 | 3 | ||||||
| 1 | 7 | 9 | 8 | 4 | 2 | |||
| 9 | ||||||||
| 8 | 9 | 6 | 3 | |||||
| 3 | 9 | 4 | 2 | 7 | 6 | |||
| 6 | 8 | 3 | 2 | |||||
| 4 | 7 | 3 |
Paused
Solved!
Keyboard shortcuts
- Arrow keys move between cells; Home and End jump to the start or end of the row.
- 1–9 enters a number (pressing the same number again clears it); Backspace, Delete or 0 clears the cell.
- N switches notes mode on or off; Shift + a number adds or removes a note.
- Ctrl + Z (Cmd + Z on a Mac) undoes; Ctrl + Y or Ctrl + Shift + Z redoes.
What makes a puzzle medium
A medium puzzle cannot be finished with singles alone. At some point every remaining cell has two or more candidates and no digit has a single home, and you need one of four patterns to break the deadlock. Medium puzzles here start with 30 to 33 givens. Across our medium bank, 92% of puzzles use a pointing pair (or triple), 17% use box/line reduction, 16% use a naked pair and 3% use a hidden pair. Most need only one or two of these moments; the rest is singles.
The four medium techniques
- Pointing pairs: if all the cells in a box that can hold a 7 lie in one row, the 7 for that row must be in this box, so you can remove 7 from the rest of the row.
- Box/line reduction: the mirror image. If a row's only possible cells for a digit all fall inside one box, remove that digit from the other cells of the box.
- Naked pairs: two cells in a unit that both have exactly the same two candidates. Those two digits are used up, so remove them from the rest of the unit.
- Hidden pairs: two digits that can only go in the same two cells of a unit. Those cells hold those digits, so any other candidates in them can go.
A good way to approach medium puzzles
Start exactly as you would with an easy puzzle and take every single you can find. When you get stuck, switch on notes mode and fill in the candidates for the cells that look most constrained (rows, columns or boxes with few gaps). With notes in place, patterns become visible: look for two cells with the same two notes, or a digit whose notes sit in a straight line inside a box. Each elimination usually unlocks a new single.
Keep “Auto-remove notes” on. Every digit you place then clears itself from the notes in its row, column and box, so your candidates stay accurate without extra work. If you are stuck, the first level of a hint names the technique and the unit, which is often enough to spot it yourself.
When to move up
Once you can find pointing pairs and naked pairs without help, hard sudoku adds the X-Wing, XY-Wing and triples. If medium still feels tough, go back to easy puzzles and practise scanning for hidden singles faster; speed on singles makes every level easier.
Frequently asked questions
How many givens does a medium puzzle have?
30 to 33 in our medium bank, 31.5 on average. The level depends on the techniques needed, not on the number of givens.
Do medium puzzles ever need guessing?
No. Every puzzle has exactly one solution and can be solved by logic using the techniques listed for its level.
How do I get a new puzzle?
Press New puzzle under the grid. Your unfinished puzzle is saved and you can come back to it.
Can I print these puzzles?
Yes. Press Print under the grid for the current puzzle, or use the printable page for sheets of 1, 4 or 6 with an answer key.
What does the hint button do?
The first press names a technique and where to look, the second highlights the cells involved, and the third makes the move and explains it. If one of your numbers is wrong, the hint tells you that first.
Can I turn off mistake highlighting?
Yes. Highlighting of numbers that do not match the solution is off by default; switch it on under Options. Two equal digits in the same row, column or box are always marked.
Updated · Written by the NineByNine team