Medium Irregular Sudoku
3
1
8
2
9
7
4
6
5
6
4
5
9
3
1
3
8
2
5
9
4
5
7
2
8
8
1
7
3
2
6
5
How to play Irregular Sudoku
Standard row and column rules apply. Each coloured region (outlined with a thick border) must also contain 1–9 exactly once. The regions replace the standard 3×3 boxes.
About Jigsaw Sudoku
Difficulty
★★★☆☆
3/5
Constraint Type
Irregular Regions
Typical Givens
24–30
Avg. Solve (Medium)
16 min
Jigsaw Sudoku (also called Irregular Sudoku) replaces the nine standard 3×3 boxes with nine irregular jigsaw-shaped regions. Each region still contains nine cells and must still contain every digit 1–9 exactly once. The rows and columns rules remain unchanged. The irregular shapes can create very different solving paths from classic Sudoku.
Solving Techniques
| Technique | Description | Level |
|---|---|---|
| Region Identification First | Identify all 9 irregular regions by their colour coding before solving. Region membership determines the third constraint unit for each cell. | Beginner |
| Region Counting | Each region must contain 1–9. Counting completed rows and columns reveals how many of each digit can still fit in each region. | Intermediate |
| Region–Row/Column Intersection | If a digit within a region is confined to one row or column, eliminate it from the rest of that row or column. | Intermediate |
| Irregular Naked Subsets | Apply naked pairs and triples within each irregular region exactly as you would within standard 3×3 boxes. | Advanced |
Average Solve Time by Difficulty
Easy
7 min
Medium
16 min
Hard
32 min
Expert
60 min