Medium Sudoku Puzzles

Medium Sudoku is where the game truly comes alive. With 30–35 starting clues, these puzzles sit at the sweet spot between accessibility and genuine challenge. You’ll still find plenty of naked singles and hidden singles to get you started, but at some point the obvious placements dry up — and that’s when the real problem-solving begins.

If you’ve been cruising through easy puzzles and want your next challenge, medium is the natural step up. It rewards careful thinking, introduces powerful new techniques, and builds the analytical foundation you’ll rely on through hard, expert, and beyond.

How Medium Differs from Easy and Hard

Understanding where medium sits in the difficulty spectrum helps you approach these puzzles with the right mindset.

Coming from Easy

Easy Sudoku can be solved entirely with naked and hidden singles — techniques that place a number directly into a cell. Medium puzzles still contain many singles, but you’ll reach points where no cell has only one possibility and no number has only one home in its unit. That’s when you need candidate elimination techniques.

The key new skills you’ll develop at medium:

  • Naked pairs: When two cells in the same row, column, or box contain the same two candidates and nothing else, those two numbers can be eliminated from all other cells in that unit. This unlocks placements that singles alone can’t find.
  • Hidden pairs: When two numbers only appear as candidates in the same two cells within a unit, all other candidates can be removed from those cells — even if those cells have additional possibilities.
  • Cross-hatching: Systematically checking where a specific number can go within a box by eliminating rows and columns where it already appears.

Moving to Hard

Hard Sudoku takes the pair logic you’ve learned and extends it. Hard puzzles frequently require pointing pairs, pointing triples, and naked triples — techniques that involve analyzing interactions between boxes and lines. Hard puzzles also have fewer starting clues (26–30), which means longer chains of deduction and more steps before a placement becomes clear.

The bridge from medium to hard is manageable if you’ve thoroughly learned pairs. Practice until you can spot naked pairs and hidden pairs without struggling, then try a few hard puzzles. You’ll find that the same logical thinking applies — just with more complexity.

Strategies for Solving Medium Sudoku

Here’s a practical workflow for tackling medium-level grids:

  1. Start with singles. Scan the entire grid for naked singles and hidden singles first. In medium puzzles, these will typically fill 40–60% of the grid before you need anything more advanced.

  2. Fill in all pencil marks. Once singles stop producing results, enable candidate mode and mark every possible number in every empty cell. Accurate pencil marks are essential — they make pairs and other patterns visible.

  3. Scan for naked pairs. Look at each row, column, and box. Do any two cells share the exact same two candidates (and only those two)? If so, eliminate those numbers from all other cells in the same unit. See our naked pair technique guide for detailed examples.

  4. Check for hidden pairs. Do any two numbers only appear in the same two cells within a unit? If so, those cells must contain those two numbers — remove all other candidates from them. Our hidden pair guide walks through this step by step.

  5. Re-scan for new singles. After eliminating candidates through pairs, new naked or hidden singles often appear. Go back to step 1 and repeat until the puzzle is solved.

  6. Stay organized. Update your pencil marks after every elimination. Stale candidate lists lead to missed patterns and errors.

Common Mistakes at the Medium Level

  • Incomplete pencil marks. Skipping candidate notation forces you to hold too much in your head. Write everything down — it’s faster in the long run.
  • Forgetting to re-scan after eliminations. Every candidate you remove potentially creates new singles. Always check the affected row, column, and box immediately.
  • Confusing naked and hidden pairs. A naked pair has exactly two candidates in two cells. A hidden pair has two numbers that only appear in two cells, but those cells may have additional candidates. Both are valuable — learn to distinguish them.
  • Guessing when stuck. If you can’t find a logical next step, you’ve likely missed a pattern. Re-check your pencil marks for accuracy before anything else.

When to Move to Hard

You’re ready for hard Sudoku when:

  • You consistently solve medium puzzles without hints.
  • You can spot naked pairs and hidden pairs quickly and confidently.
  • Your medium solving times are dropping and you want more resistance.
  • You’re curious about techniques like pointing pairs and naked triples.

Frequently Asked Questions

What techniques do medium Sudoku puzzles require? Medium puzzles require naked singles, hidden singles, plus candidate-elimination techniques like naked pairs and hidden pairs. Some medium grids may also involve simple cross-hatching.

How many starting clues do medium puzzles have? Typically 30–35, compared to 36–45 for easy and 26–30 for hard. Fewer clues means more empty cells and more complex deduction chains.

How long should a medium Sudoku take? Times vary widely — beginners at this level might spend 10–20 minutes, while practiced solvers can finish in 5–8 minutes. Focus on learning the techniques rather than speed; speed follows naturally.

Is medium harder than it looks? Medium is often described as the most “educational” difficulty level. It’s hard enough to require real thought but structured enough that you can learn techniques methodically. Many players spend the most time at this level because each puzzle teaches something new.

Explore our technique guides to deepen your understanding, or try practice puzzles that focus on naked pairs and hidden pairs specifically. When you’re ready, hard Sudoku awaits.