How to Solve Jigsaw Sudoku: A Step-by-Step Guide for Beginners

If you can solve a regular sudoku, you're about 90% of the way to solving a jigsaw sudoku — the only new thing to learn is how to read the squiggly regions that replace the usual 3x3 boxes. That's it. The rules are otherwise identical, there's no math, and you never have to guess. This step-by-step guide walks a complete beginner through that first solve, from making sense of the irregular regions to placing your opening digits with confidence. Take it slowly and the odd-shaped grid stops looking intimidating fast.

For the formal rulebook and edge cases, see the jigsaw sudoku rules. This is the friendly, hands-on version.

What you're actually looking at

A jigsaw sudoku — also known as squiggly or irregular sudoku — is a standard 9x9 grid with one change. Instead of nine tidy 3x3 boxes, the grid is divided into nine irregular, jigsaw-shaped regions, each holding exactly nine cells. These regions are usually color-coded so you can tell them apart.

The rules are the ordinary sudoku rules:

• Every row contains the digits 1 to 9, no repeats.
• Every column contains 1 to 9, no repeats.
• Every region (the squiggly shape, not a square box) contains 1 to 9, no repeats.

If you've played sudoku, only that third rule has changed shape. Everything else is exactly the same.

Step 1: Read the regions before you place anything

Your very first move isn't a move at all — it's looking. Trace each colored region with your eye and notice where it begins and ends. Some regions are compact; others snake across three or four rows. Get a feel for the shapes.

This matters because the most common beginner mistake in jigsaw sudoku is misreading which cells belong to a region. Assign one cell to the wrong region and every deduction after it goes wrong. Thirty seconds of looking saves you a restart.

Step 2: Scan for forced digits

Now solve like you would any sudoku. Pick a number that already appears a few times — say 4 — and look at each region that's missing it. A 4 can't go in any row or column that already has one, so cross those off. If a region has only one cell left where a 4 could legally sit, that's your answer.

Here's the nice surprise: because the squiggly regions stretch across more rows and columns than a square box, scanning often forces a digit sooner than in regular sudoku. The irregular shape works in your favor. Work each digit through all nine regions, then move to the next.

Step 3: Fill the forced cells

After scanning, look for cells with only one possible digit left. Pick an empty cell and ask which numbers already appear in its row, its column, and its region. Cross all of those off the list of 1 to 9. If exactly one digit survives, it's forced — write it in.

Scanning plus forced cells is enough to finish every easy jigsaw sudoku we have. You won't need anything fancier at this level.

Step 4: A quick worked example

Say a squiggly region is missing the digits 2, 6, and 9 across three empty cells. You check the first empty cell: its row already contains a 6, and its column already contains a 9. That leaves only 2, so the 2 is forced into that cell.

Now the region only needs 6 and 9 across two cells. You look at the next empty cell: its column already has a 6, so 6 can't go there — it must be 9. And the last cell takes the 6 by elimination. Three cells solved, no guessing, just the rule doing its work. The only difference from regular sudoku is that those three cells were scattered along a winding region instead of sitting in a neat square.

Step 5: When you get stuck

Every beginner hits a wall where nothing jumps out. The fixes, in order:

• Re-trace the regions. You may have misread a boundary. Confirm the colors before doubting your logic.
• Re-scan slowly, region by region. You almost certainly skipped a digit. Go 1 through 9 deliberately.
• Look for hidden singles inside a region. Sometimes a digit can only go in one cell of a region even though that cell has other candidates. These are easy to miss when the region is an odd shape.
• Start writing pencil marks. Jot the possible digits into each empty cell. Seeing the options turns a memory problem into a spotting problem.

And never guess. Our puzzles always have exactly one logical solution. A coin-flip feeling means there's a deduction you haven't found — keep looking, especially inside the squiggly regions.

Step 6: What comes next

Once scanning and forced cells feel natural, you're ready for the technique that makes jigsaw sudoku special: the Law of Leftovers, which uses the overlap between rows and regions to reveal digits nothing else can. After that, the full jigsaw sudoku strategy guide lays out every technique in order.

Where to play your first one

Open an easy jigsaw sudoku — generous givens and gentle regions make it the right place to practice tracing and scanning. Prefer paper? Grab a printable jigsaw sudoku. The best way to learn how to solve jigsaw sudoku is to solve one: trace the regions, scan for your first digit, and go.

Frequently asked questions

How do you play jigsaw sudoku?

Fill the 9x9 grid so every row, every column, and every irregular region contains the digits 1 to 9 without repeating. It's identical to regular sudoku except the nine 3x3 boxes are replaced by nine squiggly, jigsaw-shaped regions of nine cells each.

Where do you start in a jigsaw sudoku?

Start by tracing the colored regions so you know their exact shapes, then scan for forced digits the same way you would in regular sudoku. Because the regions stretch across more rows and columns than square boxes, scanning often pins down a digit surprisingly early.

Is jigsaw sudoku good for beginners?

An easy jigsaw sudoku is very beginner-friendly. It provides plenty of given digits, and the solving is ordinary sudoku logic applied to differently shaped regions. If you can finish a medium regular sudoku, you can handle an easy jigsaw sudoku.

What is the difference between jigsaw sudoku and squiggly sudoku?

There is no difference — they're two names for the same puzzle. "Squiggly sudoku" describes the wavy region shapes, while "jigsaw sudoku" compares them to jigsaw pieces. It's also called irregular or nonomino sudoku.

Do you need math to solve jigsaw sudoku?

No. The digits are just symbols, and you never add or calculate anything. Jigsaw sudoku is pure placement logic — you could swap the numbers for nine colors and the puzzle would work exactly the same.