Hard Consecutive Sudoku
5
7
6
6
1
5
8
4
3
7
1
5
9
4
3
2
9
6
1
7
7
1
9
9
2
4
5
How to play Consecutive Sudoku
Standard Sudoku rules apply. White bars appear between adjacent cells whose values differ by exactly 1. Where there is no bar, the two cells are NOT consecutive.
About Consecutive Sudoku
Difficulty
★★★☆☆
3/5
Constraint Type
Cell Relationships
Typical Givens
18–24
Avg. Solve (Medium)
16 min
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.
Solving Techniques
| Technique | Description | 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 Time by Difficulty
Easy
7 min
Medium
16 min
Hard
32 min
Expert
58 min