What changes at Medium?
A Medium puzzle starts with 30 givens — six fewer than Easy. That doesn't sound like much, but it's enough that the board stops handing you free moves. You'll clear the obvious cells quickly, then hit your first honest pause: a grid where nothing jumps out and you actually have to look.
This is where Sudoku gets interesting. The puzzle is still gentle — every step is findable — but you start working for the solution instead of just reading it off. It's the level most people settle into for their daily grid.
Techniques that carry you through
Scanning for singles still does most of the job, but Medium is where a second idea earns its place:
- Hidden Single in Sudoku — A digit that can legally go in only one cell of a unit, even if that cell shows other candidates.
- Naked Pair — Two cells in a unit holding the same two candidates claim those digits, removing them elsewhere in the unit.
The naked pair is the big one to add here: two cells in a unit that share the same two candidates lock those digits away from everything else nearby, which often frees up a single you couldn't see before. It's the first taste of eliminating rather than just placing.
Where pencil marks start to matter
On Easy you can keep everything in your head. On Medium you'll hit a spot where you can't — and that's your cue to start pencilling in candidates. You don't have to mark the whole board; just note the possibilities in the region you're stuck on, and the naked pair (or a hidden single you'd missed) usually appears.
- Mark the tricky corner, not the easy one. Spend your notes where the grid is fighting back.
- Re-scan after every placement. One new number can turn three uncertain cells into certainties.
Ready for a real fight? Hard Sudoku is next — the level where scanning alone runs out and method takes over.