Medium Thermo Sudoku
Ready to sharpen your skills? Medium Thermo Sudoku puzzles introduce interactions between the variant constraint and classic Sudoku techniques. You'll need to combine both skill sets to progress.
What to expect at Medium level
Medium Thermo Sudoku puzzles require you to combine the variant constraint with standard Sudoku deduction - Naked pairs, hidden singles, and unit scans. The constraint is more tightly woven into the grid, so you'll need to think a few steps ahead.
Best suited for players comfortable with Easy Thermo Sudoku who want to build their pattern recognition.
Difficulty overview
About Thermo Sudoku
Thermo Sudoku overlays thermometer shapes on the grid. Each thermometer has a bulb (circle) at one end and a tip at the other. The digits along any thermometer must strictly increase from the bulb to the tip. Combined with standard Sudoku constraints, this creates powerful chains of deductions — knowing the bulb is at least 1 and the tip is at most 9, you can calculate the range of valid values for each cell on the thermometer based on its position.
Solving Techniques for Medium Level
| Technique | Description | Level |
|---|---|---|
| Range Restriction from Length | A thermometer with N cells must use N strictly increasing distinct values. The bulb is at least 1 and the tip is at most 9, giving a calculable valid range for each cell. | Beginner |
| Minimum/Maximum Bounding | The bulb value is ≤ 9 − (N − 1). The tip value is ≥ N. Apply these bounds immediately to prune all thermometer candidates. | Beginner |
| Overlapping Thermometer Deduction | Two thermometers sharing a cell give tighter combined bounds than either alone. | Intermediate |
| Short vs. Long Thermometers | A 2-cell thermometer is simply a greater-than relationship. A 9-cell thermometer forces exactly 1–9 in order. | Intermediate |
Master these, then take on Hard Killer Sudoku to learn Advanced techniques.