Anti-Consecutive Sudoku
Orthogonally adjacent cells may not contain consecutive digits
Easy
Anti-Consecutive Sudoku Easy
Medium
Anti-Consecutive Sudoku Medium
Hard
Anti-Consecutive Sudoku Hard
Expert
Anti-Consecutive Sudoku Expert
What is Anti-Consecutive Sudoku?
Anti-Consecutive Sudoku (a stricter form of Non-Consecutive Sudoku) imposes the rule that no two orthogonally adjacent cells may contain consecutive integers. This variant often requires fewer given digits because the constraint alone eliminates so many candidate pairs. It is sometimes combined with Anti-King or Anti-Knight to create extremely constrained puzzles.
At a Glance
| Constraint type | Anti-Constraints |
| Typical givens | 18–24 |
| Difficulty rating | ★★★☆☆ 3/5 |
| Avg. solve time — Easy | 5 min |
| Avg. solve time — Medium | 13 min |
| Avg. solve time — Hard | 26 min |
| Avg. solve time — Expert | 48 min |
How to Solve Anti-Consecutive Sudoku
| Technique | What it does | Level |
|---|---|---|
| Global Candidate Pruning | For every filled cell, remove its ±1 neighbours from all orthogonally adjacent cells immediately. | Beginner |
| Digit 5 is Most Constrained | 5 cannot be adjacent to 4 or 6. Use this to restrict placement of 5 across the entire grid. | Intermediate |
| Chain Propagation | Placing a digit propagates constraints along rows and columns, often triggering a cascade of forced placements. | Intermediate |
| Forbidden Pair Maps | Build a map of forbidden digit pairs for each adjacent pair of cells and use it to eliminate candidates systematically. | Advanced |
Average Solve Times
Easy
5 min
Medium
13 min
Hard
26 min
Expert
48 min
Frequently Asked Questions
Which cells count as adjacent?
Only orthogonally adjacent cells — sharing an edge horizontally or vertically. Diagonal neighbours are unaffected.
Is Anti-Consecutive different from Non-Consecutive?
They use the same constraint — no two orthogonally adjacent cells may contain consecutive digits. Anti-Consecutive is another name for the same variant.