Easy Renban Sudoku
4
5
7
9
1
9
5
4
8
9
7
6
4
8
5
6
4
9
8
5
1
8
3
2
5
7
6
3
4
4
1
3
6
8
4
6
2
1
How to play Renban Sudoku
Standard Sudoku rules apply. Each purple line must contain a set of consecutive digits in any order. The line length tells you exactly how many consecutive numbers are needed - E.g. a 4-cell line might contain 3,6,4,5.
About Renban Sudoku
Difficulty
★★★★☆
4/5
Constraint Type
Line Constraints
Typical Givens
20–28
Avg. Solve (Medium)
22 min
Renban Sudoku draws purple lines on the grid. The digits on any purple line must form a set of consecutive integers (like 3,4,5 or 7,8), though they can appear in any order along the line. The length of the line tells you exactly how many consecutive numbers are involved. This creates powerful range restrictions: a 5-cell Renban line can only span 5 consecutive values from the possible range 1–9.
Solving Techniques
| Technique | Description | Level |
|---|---|---|
| Length-Based Range | A Renban line of length L must contain L consecutive integers. The starting value is between 1 and 10−L, giving 10−L possible ranges. | Beginner |
| Shared Cell Intersection | If two Renban lines share a cell, that cell's value must fit both lines' consecutive ranges. Intersect the ranges to find valid values. | Intermediate |
| Single-Range Reduction | When a Renban line's valid range reduces to a single starting value, all cell values are fully determined (in some order). | Intermediate |
| Renban–Box Interaction | Digits on a Renban line within one box restrict the box's remaining cells. Use box uniqueness to narrow the line's range. | Advanced |
Average Solve Time by Difficulty
Easy
10 min
Medium
22 min
Hard
42 min
Expert
72 min