Jigsaw, Squiggly, Irregular: Why This Sudoku Has Five Names

If you've seen this puzzle called "squiggly sudoku" on one site and "jigsaw sudoku" on another — and then "irregular," "nonomino," or even "geometric" sudoku somewhere else — you're not imagining things. They are all exactly the same puzzle: a standard 9x9 sudoku where the nine 3x3 boxes are replaced by nine irregular, jigsaw-shaped regions. One puzzle, five common names. Each one tells you something about how people see the puzzle or where it came from. This article untangles the aliases so you always know what you're playing, whatever a given site decides to call it.

Want to just play it under any name? It's right here at jigsaw sudoku.

They're all the same puzzle

Whatever the label, the rules are identical to regular sudoku with one twist: every row and every column still holds the digits 1 to 9 once, but instead of square boxes, the grid is divided into nine irregular regions of nine cells each, and each region must also contain 1 to 9. If a sudoku has squiggly, color-coded regions instead of neat 3x3 boxes, it's this puzzle — no matter what name sits at the top of the page. (New to it? The jigsaw sudoku rules lay it out.)

So why so many names? Because the puzzle spread across different communities — newspapers, mathematicians, software makers, non-English markets — and each reached for a name that made sense to them.

Jigsaw sudoku

The most common English name. It compares the irregular regions to the interlocking pieces of a jigsaw puzzle, which is exactly what they look like. Major outlets like krazydad and The Sunday Telegraph use it, and it has roughly three times the search traffic of any other name — which is why most sites (including this one) lead with it.

Squiggly sudoku

The second most common name, and a popular one in apps and casual puzzle circles. "Squiggly" describes the wavy, snaking boundaries of the regions in plain, friendly language. It's a substantial name in its own right — plenty of people search specifically for "squiggly sudoku" without ever calling it jigsaw. If that's the term you learned it by, you're in good company.

Irregular sudoku

The most descriptive, neutral name, common in enthusiast and reference contexts. It simply states the defining feature: the regions are irregular rather than the standard regular 3x3 boxes. You'll often see it in technique discussions and on wiki-style pages where precision matters more than flavor.

Nonomino sudoku

The mathematical name. A nonomino is a shape made of nine connected squares (the nine-cell cousin of the more familiar tetromino from falling-block games). Since each region in this puzzle is a nine-cell connected shape — a nonomino — mathematicians and academics call it nonomino sudoku. It's Wikipedia's preferred term. If you want to sound precise at a puzzle convention, this is the word.

Geometric sudoku

The least common of the five in English, but it shows up in some non-English markets and software. It emphasizes that the regions are defined by their geometry — their shape — rather than by a fixed grid pattern. You're most likely to meet it as a translation on multi-language puzzle sites.

A quick glossary

Here's every name you're likely to meet, all pointing to the same puzzle:

• Jigsaw sudoku — the dominant English name; regions look like jigsaw pieces.
• Squiggly sudoku — friendly, describes the wavy region boundaries.
• Irregular sudoku — neutral and descriptive; regions aren't regular boxes.
• Nonomino sudoku — the mathematical term; each region is a nine-cell nonomino.
• Geometric sudoku — emphasizes shape-defined regions; common in some translations.

Does the name change how you play?

Not at all. The strategy is the same regardless of the label. Trace the regions, scan each digit through all nine of them, and when you stall, reach for the Law of Leftovers — the technique unique to irregular grids. That approach works whether the site says "jigsaw," "squiggly," or "nonomino." For the full method, see the jigsaw sudoku strategy guide, and for where these names came from over time, the history of jigsaw sudoku.

The takeaway: don't let the names confuse you. They're all doorways into the same satisfying puzzle. Pick whichever your favorite site uses, and start solving.

Frequently asked questions

Is squiggly sudoku the same as jigsaw sudoku?

Yes, exactly the same. "Squiggly sudoku" and "jigsaw sudoku" are two names for a sudoku where the nine 3x3 boxes are replaced by nine irregular regions. "Squiggly" describes the wavy region shapes; "jigsaw" compares them to puzzle pieces. The rules and solving techniques are identical.

What is irregular sudoku?

Irregular sudoku is another name for jigsaw or squiggly sudoku. It refers to the fact that the nine regions are irregular shapes rather than the regular 3x3 boxes of standard sudoku. Each region still must contain the digits 1 to 9 once.

What is a nonomino sudoku?

A nonomino sudoku is the mathematical name for jigsaw sudoku. A nonomino is a shape made of nine connected squares, and since each region in the puzzle is a nine-cell connected shape, academics call it nonomino sudoku. It's the term Wikipedia uses.

Why does jigsaw sudoku have so many names?

The puzzle spread through different communities — newspapers, mathematicians, software makers, and non-English markets — and each adopted a name that fit. "Jigsaw" and "squiggly" describe the look, "irregular" describes the structure, "nonomino" is the mathematical term, and "geometric" appears in some translations.

Which name should I search for?

"Jigsaw sudoku" has the most results and the largest community, so it's the best general search term. But "squiggly sudoku" is also widely used, and "irregular" or "nonomino sudoku" will find more technical, enthusiast-oriented content.