Anti-Consecutive Sudoku
5
9
7
1
3
1
2
3
7
2
4
1
8
9
6
7
2
3
8
5
2
4
7
1
3
4
7
1
9
6
8
5
2
2
6
9
1
8
Mistakes
0/3
Score
-
Time
00:00
Progress0%
Easy · Anti-Consecutive Sudoku
Switch difficulty above ↑
How to play Anti-Consecutive Sudoku
Standard Sudoku rules apply. Extra rule: no two orthogonally adjacent cells (sharing an edge) may contain consecutive digits. If a cell holds 5, all four neighbours must avoid 4 and 6.
Full guide →
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
What is Anti-Consecutive Sudoku?
Anti-Consecutive Sudoku is a variant where no two orthogonally adjacent cells (horizontally or vertically neighbouring) may contain consecutive digits. The rule applies everywhere on the grid without any markers. Standard Sudoku rules also apply throughout.
How is Anti-Consecutive different from Non-Consecutive Sudoku?
Anti-Consecutive and Non-Consecutive Sudoku are the same constraint — the name is used interchangeably by different puzzle communities. Both mean: no two horizontally or vertically neighbouring cells may hold digits that differ by exactly 1.
Which digit placements trigger the most eliminations?
Digits in the middle of the range (4, 5, 6) eliminate two consecutive neighbours simultaneously. Placing a 5 removes both 4 and 6 from all four orthogonal neighbours, and placing those 4s and 6s in turn removes 3 and 7 from their neighbours — creating a cascade effect. Starting with central digits often unlocks large portions of the grid.
Is Anti-Consecutive Sudoku accessible for beginners?
The rule is simple and the early eliminations are satisfying and obvious. Easy puzzles are well-suited for Sudoku players who want a step up from classic without learning arithmetic (like Killer or Arrow). The non-consecutive constraint is entirely logic-based.
What is the best approach to Anti-Consecutive Sudoku?
Treat the anti-consecutive constraint as an additional elimination layer. After every digit placement, immediately update all four orthogonal neighbours to remove ±1 from their candidate lists. The more given digits you have to start with, the more these cascade eliminations interact.
How long does Anti-Consecutive Sudoku take to solve?
Easy puzzles take 5–15 minutes. Medium puzzles run 15–30 minutes. Hard puzzles average 30–55 minutes and expert puzzles can take 60–90 minutes. Expert puzzles with very few given digits rely entirely on the anti-consecutive constraint for deductions.