How to play Jigsaw Sudoku
Each row and each column holds 1–9 once, just like classic Sudoku. Instead of 3×3 boxes, the grid is divided into nine irregular regions marked with thick borders, and each region holds 1–9 once as well.
Use the shapes against the puzzle
Irregular regions create overlaps that do not exist in normal Sudoku. When a region pokes one cell into a neighbouring row, that cell is heavily constrained by both. Look for regions that fit almost entirely inside two or three rows: the few cells that stick out are often forced by the rule of 45, explained on the cage combinations page.
Singles and pairs work exactly as described in the strategy guide. Just read "box" as "region".
Ask the puzzle coach
Stuck on a rule or a tactic? Ask in plain words. The coach only talks puzzles, and the answer is written for you on the spot.
Questions players ask
What is Jigsaw Sudoku?
Sudoku where the nine 3×3 boxes are replaced by nine irregular shapes of nine cells each. Rows and columns work as usual; each shape must also contain 1–9 once. It is also called Irregular Sudoku, Squiggly Sudoku or Nonomino.
Does the rule of 45 work here?
Yes, and it is more useful than in classic Sudoku. Because shapes bulge into neighbouring rows, counting how many cells of a set of regions stick out of a band of rows often forces a digit.
Are the shapes different every game?
Yes. A new set of connected nine-cell regions is drawn for every puzzle, then a solution is built and clues are removed while keeping the answer unique.