Play Medium Sudoku Online — Balanced Daily Mental Workout
Strategic Logic Puzzles Requiring Candidate Note-Taking and Hidden Singles
Medium Sudoku strikes the sweet spot between relaxing deduction and stimulating mental exercise. With 32 to 37 starting clues, direct visual scanning alone is no longer sufficient; you will need to utilize pencil marks (candidate notes) and uncover Hidden Singles to triumph.
Mastering "Hidden Singles": The Key to Medium Sudoku
Unlike a Naked Single (where only one candidate fits into a cell), a Hidden Single occurs when a cell has multiple candidate options, but a specific digit can ONLY go in that one square within its row, column, or 3×3 box.
Hidden singles often evade casual scanning because the target cell may seem cluttered with notes. Always ask: "In this row or box, where else can digit X legally go?" If the answer is nowhere else, place that digit immediately.
- Turn on Pencil Notes mode (press N) to mark 2–3 likely candidates per cell.
- Systematically audit each digit from 1 to 9 inside every 3×3 subgrid.
- When you place a digit, immediately clear that candidate from intersecting peers.
The Power of Snyder Notation for Speed and Accuracy
Named after world Sudoku champion Thomas Snyder, Snyder Notation is the practice of only writing pencil notes for a digit in a 3×3 box when that digit has exactly TWO possible locations.
This keeps your board clean, prevents visual overload, and instantly exposes pointing pairs and hidden pairs as you fill in the grid.
Frequently Asked Questions
How is Medium Sudoku different from Easy Sudoku?▼
Medium Sudoku contains fewer starting clues (typically 32–37 vs 38–46) and intentionally leaves fewer direct singles. Solving requires pencil notes and finding Hidden Singles.
How long should a Medium Sudoku puzzle take to solve?▼
Most intermediate solvers finish a Medium Sudoku in 7 to 15 minutes. With regular practice and Snyder notation, times under 6 minutes are achievable.
What is the best strategy when I get stuck on Medium Sudoku?▼
When stuck, systematically examine each row, column, and box for numbers that only have one legal placement remaining. You can also tap the Smart Hint button for step-by-step guidance.