What is Jigsaw Sudoku?
Jigsaw Sudoku is a logic puzzle that keeps the familiar 9x9 grid and the digits 1 to 9, but throws out the tidy 3x3 boxes. In their place are nine irregular regions — interlocking nonomino shapes that twist and curve across the board like pieces of a jigsaw. Because the regions are no longer square, the puzzle is also known as irregular sudoku or squiggly sudoku. Each region still holds nine cells, so the underlying promise is unchanged: fill the grid so that every row, column, and region contains all nine digits exactly once.
How to Play Jigsaw Sudoku
Start the way you would with any sudoku: scan each row and column for digits that can only go in one place. The difference is the third constraint — instead of a 3x3 box, you check each of the nine irregular regions. Trace a region's outline carefully before you commit a number, because a squiggly shape can wander across four or five rows. Pencil in candidates, eliminate digits that already appear in the same row, column, or region, and a single forced answer will usually reveal itself. Use the keypad to place a digit and notes mode to track candidates.
Jigsaw vs. Classic Sudoku
Classic sudoku and jigsaw sudoku share the same goal and the same digits, so every technique you already know still applies. What changes is geometry. In classic sudoku the nine boxes line up in a predictable 3x3 lattice; in jigsaw sudoku the irregular regions bend around the grid, which removes the visual shortcuts your eye relies on. That makes scanning slower and forces you to read the bold region outlines rather than assume a block. Many solvers find an easy jigsaw grid plays like a medium classic one — the logic is identical, but the irregular regions demand more deliberate attention.
Tips & Strategy
Lean on the region-sum idea: every region, row, and column totals 45, so when a region pokes just one cell outside a row or column you can often deduce that cell by subtraction. Hunt for the most constrained regions first — narrow, stretched shapes tend to intersect many lines and yield quick singles. Always read the squiggly outlines before placing a digit; a number that looks safe in a row may already sit in the same irregular region. Finally, keep candidate notes tidy. In irregular sudoku the regions overlap your sight lines in unfamiliar ways, and accurate pencil marks prevent costly mistakes.
More Sudoku to Play
Prefer arithmetic to geometry? Try Killer Sudoku, the cage-sum variant, or explore every option on our Sudoku variants hub. You can also go back to the classic Daily Sudoku puzzle.