Jigsaw Sudoku
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How to play Jigsaw 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.
Full guide →
Irregular jigsaw-shaped regions replace the standard 3×3 boxes
Easy
Jigsaw Sudoku Easy
Medium
Jigsaw Sudoku Medium
Hard
Jigsaw Sudoku Hard
Expert
Jigsaw Sudoku Expert
What is Jigsaw Sudoku?
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.
At a Glance
| Constraint type | Irregular Regions |
| Typical givens | 24–30 |
| 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 | 60 min |
How to Solve Jigsaw Sudoku
| Technique | What it does | 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 Times
Easy
7 min
Medium
16 min
Hard
32 min
Expert
60 min
Frequently Asked Questions
What is Irregular Sudoku?
Irregular Sudoku (also called Jigsaw Sudoku) replaces the standard nine 3×3 boxes with nine irregularly-shaped regions of exactly nine cells each. Every row, column, and irregular region must still contain the digits 1–9 exactly once. The regions are colour-coded or outlined with thick borders.
How do I identify the irregular regions?
Each region is shaded in a distinct colour or enclosed by thicker lines. Count the cells in each region to confirm it has exactly nine. The regions are always connected — no region is split across the grid — but they can have any shape as long as they tile the full 9×9 grid.
Is solving Irregular Sudoku different from classic Sudoku?
The logic is identical — you use the same techniques (naked pairs, hidden singles, pointing pairs, etc.) — but the non-rectangular region shapes create different constraint interactions. A region that snakes diagonally creates eliminations in many different rows and columns simultaneously, which can feel unintuitive at first.
Is Irregular Sudoku harder than regular Sudoku?
At easy difficulty, Irregular Sudoku can be harder because the region shapes are less predictable than 3×3 boxes. At higher difficulties, experienced Sudoku players often find it comparably challenging — the same techniques apply, just with different geometry.
What is the best strategy for Irregular Sudoku?
Trace each region carefully before starting — understand its shape and which rows and columns it spans. Regions that span many different rows and columns create more powerful constraints. Focus on regions with the most given digits first, then use pointing pairs to transfer information between regions and lines.
How long does Irregular Sudoku take to solve?
Easy puzzles take 8–20 minutes. Medium puzzles run 20–40 minutes. Hard and expert puzzles can take 45–90 minutes. Familiarity with jigsaw region shapes speeds up solving considerably after a few practice puzzles.