Consecutive Sudoku
Bars between cells mean those two digits are consecutive
Easy
Consecutive Sudoku Easy
Medium
Consecutive Sudoku Medium
Hard
Consecutive Sudoku Hard
Expert
Consecutive Sudoku Expert
What is Consecutive Sudoku?
Consecutive Sudoku marks bars between pairs of adjacent cells. A bar means the two digits in those cells differ by exactly 1 — they are consecutive. When used with the negative constraint (no bar = not consecutive), this gives information about every adjacent pair in the entire grid, creating a powerful constraint network.
At a Glance
| Constraint type | Cell Relationships |
| Typical givens | 18–24 |
| Difficulty rating | ★★★☆☆ 3/5 |
| Avg. solve time — Easy | 7 min |
| Avg. solve time — Medium | 16 min |
| Avg. solve time — Hard | 32 min |
| Avg. solve time — Expert | 58 min |
How to Solve Consecutive Sudoku
| Technique | What it does | Level |
|---|---|---|
| Negative Constraint Power | Where no bar appears, the two cells are guaranteed non-consecutive. Every unmarked adjacent edge tells you something — treat absent bars as constraints. | Beginner |
| Bar Pair Enumeration | A bar means the digits differ by exactly 1. List all valid pairs: (1,2), (2,3), …, (8,9). Use row/column context to narrow which pair fits. | Beginner |
| Consecutive Chain | Three cells connected by two bars form a run of three consecutive digits (in some order). Enumerate the 7 possible runs: {1,2,3}, {2,3,4}, …, {7,8,9}. | Intermediate |
| Isolated Digit Detection | A digit surrounded on all four sides by non-bar edges has no consecutive neighbour — highly constrained within a local area. | Advanced |
Average Solve Times
Easy
7 min
Medium
16 min
Hard
32 min
Expert
58 min
Frequently Asked Questions
What does 'consecutive' mean?
Two digits are consecutive if they differ by exactly 1, e.g. 3 and 4, or 7 and 8.
Is the negative constraint used?
Yes — an unmarked adjacent pair guarantees the digits are NOT consecutive.