Jigsaw Sudoku

Replace square boxes with nine irregular regions.

Rules

Each row and column contains 1 through 9 once. Each outlined nine-cell region also contains 1 through 9 once. The irregular regions replace ordinary boxes; do not enforce invisible 3 by 3 boxes unless the puzzle explicitly includes both rule sets.

A visual example

Jigsaw Sudoku example diagram — The diagram has nine outlined, connected regions of nine cells each. Near the top, two cells cross the usual box boundary. Track the actual thick outline to decide which region a cell belongs to.

How to start

Scan a region's missing digits while checking its crossing rows and columns. If all positions for a digit within one region lie in a single row, that digit can be removed from other cells in the row outside the region. The familiar interaction logic still works with an irregular shape.

A mistake to avoid

Color is only a visual aid. Follow the region boundaries, especially around narrow protrusions. This diagram explains regions; it is not an unsolved puzzle with a guaranteed unique solution.

Keep learning

Review the standard rules and worked solving techniques. Our daily game and printable packs use standard Sudoku rules; they do not play this variant.