Non-Consecutive Sudoku
6
3
8
4
8
1
5
3
5
2
4
8
9
3
4
8
2
4
6
9
7
1
7
2
6
3
7
5
4
9
1
5
3
7
3
4
1
6
Mistakes
0/3
Score
-
Time
00:00
Progress0%
Easy · Non-Consecutive Sudoku
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How to play Non-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 →
No two orthogonally adjacent cells may contain consecutive digits
Easy
Non-Consecutive Sudoku Easy
Medium
Non-Consecutive Sudoku Medium
Hard
Non-Consecutive Sudoku Hard
Expert
Non-Consecutive Sudoku Expert
What is Non-Consecutive Sudoku?
Non-Consecutive Sudoku imposes a global constraint: no two cells that share an edge (orthogonally adjacent) can contain consecutive digits. So if a cell contains 5, all its neighbours must avoid 4 and 6. This single rule dramatically limits candidate placements and can reduce a standard givens count while still producing a uniquely solvable puzzle.
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 Non-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 Non-Consecutive Sudoku?
Non-Consecutive Sudoku is a variant where no two horizontally or vertically adjacent cells may contain consecutive digits. There are no markers on the grid — the non-consecutive rule applies globally to every pair of neighbours. Standard Sudoku rules also apply.
How does the global non-consecutive rule constrain the grid?
Every pair of adjacent cells cannot differ by exactly 1. This means you cannot place a 4 next to a 3 or a 5. For every digit you place, you must eliminate that digit ±1 from all orthogonal neighbours. This propagates eliminations across the entire board immediately after every placement.
Which digits are most affected by the non-consecutive rule?
Digits 1 and 9 can only be invalid next to 2 and 8 respectively — so they are least affected. Digit 5 cannot be adjacent to either 4 or 6, which is a moderate restriction. Digits 4, 5, and 6 are most affected because they are adjacent to two common digit pairs simultaneously.
Is Non-Consecutive Sudoku harder than regular Sudoku?
Yes, typically. The global constraint eliminates many more candidates than standard rules alone. Easy puzzles are accessible and resolve quickly. Hard and expert puzzles compensate with fewer given digits, making the non-consecutive constraint the primary source of all deductions.
What is the best first strategy for Non-Consecutive Sudoku?
After placing each digit, immediately mark all orthogonal neighbours as unable to hold ±1. Scan rows and columns for digits that can now only go in one cell due to these combined eliminations. Digit 5 is particularly useful as a placement anchor — wherever 5 is placed, both 4 and 6 are eliminated from all four neighbours.
How long does Non-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. Non-Consecutive Sudoku rewards players who apply the constraint globally and systematically after every move.