How Sudoku works
Medium puzzles open with 36 clues, nine fewer than easy, and that gap is where scanning alone stops being enough. You will hit positions where no digit is immediately forced and the next move has to come from a hidden single: a digit that fits in only one cell of a row, column or box, even though that cell has several candidates of its own.
This is the level where pencil notes start paying for themselves. Fill in candidates for the cells in whichever box is most constrained, and the hidden singles usually become visible immediately. Pointing pairs also appear here, where a digit within a box is confined to a single row or column and can therefore be eliminated from the rest of that line.
Expect 10 to 20 minutes. Medium is the level most casual solvers settle at long term, because it needs real technique without demanding the extended candidate bookkeeping that hard and expert grids require.
Medium Sudoku at a glance
| Medium | |
|---|---|
| Starting clues | 36 |
| Typical solve time | 10 – 20 minutes |
| Techniques needed | Hidden singles, pointing pairs |
| Empty cells | 45 |
| Pencil notes | Selectively |
How to solve faster
- Learn to spot hidden singles. A hidden single is a digit that fits in only one cell of a row, column or box, even though that cell has several candidates of its own. This is the technique that separates medium from easy, and it is the one worth drilling deliberately.
- Pencil in candidates for one box at a time. Filling notes across the whole grid at this level is more work than the puzzle needs. Do it for the most constrained box, extract what you can, then move on.
- Look for pointing pairs when you stall. When a digit inside a box can only go in one row or column of that box, it can be eliminated from the rest of that line elsewhere on the grid. Medium puzzles usually hinge on one or two of these.
Frequently asked questions
What makes a medium Sudoku harder than easy?
Thirty-six clues instead of forty-five. That gap means scanning alone runs out partway through and you need hidden singles and pointing pairs to finish.
Do I need pencil notes for medium Sudoku?
Sometimes, and selectively. Full grid notation is overkill, but noting candidates in the two or three most constrained boxes usually reveals the hidden single you need.
How long does a medium Sudoku take?
Ten to twenty minutes for most solvers. Experienced players finish in five to eight. Long pauses partway through are normal at this level and are usually where a hidden single is waiting.
Is medium a good level to stay at?
For most casual solvers, yes. It demands real technique without requiring the full candidate bookkeeping that hard and expert grids need, which keeps it enjoyable rather than laborious.