Play Jigsaw Sudoku Online
In a jigsaw sudoku the nine blocks are no longer tidy 3x3 squares but irregular regions that interlock like pieces of a puzzle. The rules stay the same — but because the shapes change, your practised eye stops working for you. At Sudoku Sagax there are 800 levels, ad-free and with no sign-up required.
What is a jigsaw sudoku?
A jigsaw sudoku is a 9x9 sudoku whose nine regions are not rectangular. Instead of the familiar 3x3 blocks there are irregular areas of nine connected squares each, with their borders drawn clearly on the board. Some snake across the grid as a narrow band, others sit as compact clumps.
You will also see it called squiggly sudoku or nonomino sudoku; in German it goes by Chaos-Sudoku. All the same puzzle.
The appeal lies precisely in the fact that practised perception no longer carries you. In classic sudoku you scan blocks without really looking — here you have to trace each region deliberately every time. That makes even easy levels pleasantly unfamiliar.
The rules, explained simply
The rules are the same as in sudoku; only the shape of the regions changes:
- Rows and columns. Every row and every column contains each digit from 1 to 9 exactly once — unchanged.
- Regions instead of blocks. Each of the nine irregular regions also contains every digit exactly once. Every region is made of nine connected squares.
- The borders are visible. Bold dividing lines on the board show which squares belong to which region.
Nothing else changes. Every puzzle has exactly one solution, and guessing is never required.
Techniques for jigsaw sudoku
Two habits from ordinary sudoku stop working — and others take their place:
- Trace the region borders deliberately. The most common mistake is checking a 3x3 square out of habit. Follow the outline of the region with your eye before you place a digit.
- Start with the narrow regions. Regions that stretch across several rows overlap many rows and columns and are therefore tightly constrained. That is where the quickest deductions are.
- Use the containment rule. If a region sits entirely within two rows, then the digits missing from those rows outside the region must go in the remaining squares. Overlaps like this come up more often here than in classic sudoku.
- Keep notes consistently. Because the eye does not take the regions in automatically, pencil marks pay off more here than in a normal sudoku.
Jigsaw sudoku at Sudoku Sagax
You will find jigsaw sudoku from the home screen under "All game types". There are 800 levels of its own, a separate leaderboard and its own trophy. Every level you solve counts towards your daily streak and the shared points pool.
Regions are separated by bold lines so they stay legible on a phone as well. Each puzzle is generated from its level number and has exactly one solution — the same level looks identical for everyone.
Notes, error highlighting, hints and undo work as they do in classic sudoku. Everything runs in the browser, ad-free, with no trackers and locally served fonts.
Frequently asked questions
What is a jigsaw sudoku?
A jigsaw sudoku is a 9x9 sudoku whose nine regions are not 3x3 blocks but irregular areas of nine connected squares each. The row and column rules are unchanged. In German the variant is known as Chaos-Sudoku.
What is the difference between jigsaw sudoku and squiggly sudoku?
There is none — they are different names for the same puzzle, along with nonomino sudoku and the German Chaos-Sudoku.
Is jigsaw sudoku harder than normal sudoku?
It feels harder at first, because a practised eye does not take in the regions automatically and every border has to be traced deliberately. The logic itself is identical, and perception adjusts after a few puzzles.
How do you start a jigsaw sudoku?
With the most oddly shaped regions. Regions that stretch a long way across rows or columns overlap a great many units and are therefore the most constrained — that is where the first digits come fastest.