Medium Odd / Even Sudoku
Ready to sharpen your skills? Medium Odd / Even 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 Odd / Even 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 Odd / Even Sudoku who want to build their pattern recognition.
Difficulty overview
About Odd / Even Sudoku
Odd/Even Sudoku marks certain cells as odd (often shaded grey) or even (often circled). Odd cells must contain one of 1, 3, 5, 7, 9 and even cells must contain one of 2, 4, 6, 8. This halves the candidate set for marked cells immediately, creating powerful restrictions without providing specific digits.
Solving Techniques for Medium Level
| Technique | Description | Level |
|---|---|---|
| Immediate Candidate Halving | Marked cells instantly reduce to 5 odd candidates (1,3,5,7,9) or 4 even candidates (2,4,6,8). Apply this before any other technique. | Beginner |
| Parity Counting per Box | Count how many odd-marked and even-marked cells are in each box to verify the digit distribution is achievable. | Intermediate |
| Parity-Chain Elimination | If a row must contain exactly four even digits, and three positions are already even-marked, the fourth must come from the remaining unmarked cells. | Intermediate |
Master these, then take on Hard Killer Sudoku to learn Advanced techniques.