Jigsaw Sudoku (Irregular Sudoku)

It feels different rather than strictly harder. You lose the familiar 3x3 box patterns, which takes some getting used to, but the odd region shapes create eliminations classic Sudoku never gives you. A region that snakes across four rows restricts all four of them at once. The puzzles on this page sit at a comfortable middle difficulty, so they are a fair introduction to the variant.

Only the regions change. The 9x9 grid, the digits and the row and column rules are identical to classic Sudoku. Instead of nine square boxes, the grid is divided into nine irregular regions, each shaded on the board so you can see its boundaries at a glance.

The irregular regions interlock like jigsaw puzzle pieces, which is where the name comes from. The same variant is sold in books and newspapers as Irregular Sudoku, Squiggly Sudoku, Nonomino Sudoku or Geometric Sudoku. They all follow the same rules.

Yes. Every puzzle on this page is generated fresh when the page loads, and a verification step confirms it has exactly one valid solution before you see it. No guessing is ever required.

Naked singles, hidden singles and pairs all work exactly as they do in classic Sudoku. The technique to add is region and line interaction: when all of a digit's possible cells within a region fall on one row or column, that digit can be removed from the rest of that row or column. Because the regions have odd shapes, this comes up far more often than the box version does in classic Sudoku.

Yes. Jigsaw Sudoku on SudokuPuzzleHub is completely free, needs no sign-up or account, and works in any desktop or mobile browser. Notes, hints and dark mode are all included.