Medium Sudoku
Medium is where Sudoku becomes a thinking game. Singles run out, and you start eliminating candidates with patterns.
Medium puzzles need techniques beyond singles: naked pairs, hidden pairs, pointing pairs and box-line reduction. They all work by eliminating candidates, so you need notes. Learn them one at a time.
How to use the board
- Tap a cell, then a digit. On a keyboard, use 1 to 9, Backspace to erase and the arrow keys to move.
- Turn Notes on to write small candidate digits. Press N on a keyboard.
- Hint finds a naked or hidden single and tells you which one it is.
- Your game is saved in this browser. Nothing is sent anywhere.
What changes at Medium
At Easy, every move places a digit. At Medium, some moves only remove a candidate, and a later single appears because of it. That is why notes matter: elimination moves are invisible without them. Start with how to use notes.
The four Medium techniques
- Naked pair: two cells in a unit that share the same two candidates.
- Hidden pair: two digits that fit in only the same two cells of a unit.
- Pointing pair: a digit in a box confined to one row or column.
- Box-line reduction: a digit in a row or column confined to one box.
A routine for stuck moments
- Fill in notes for every empty cell.
- Scan each box for a digit that sits on a single line (pointing pairs).
- Scan each row and column for the same inside one box (box-line).
- Look for two cells with the same two candidates (naked pair).
Frequently asked questions
Which techniques does Medium use?
Naked pairs, hidden pairs, pointing pairs and box-line reduction, plus singles.
Do I need notes at Medium?
Yes. Most Medium moves remove candidates, and you cannot see that without notes.
I keep getting stuck at Medium. What now?
Use the step-by-step solver on your grid. It names the technique so you know what to look for.