🧩 How to play Jigsaw Sudoku (Irregular)

By Miguel Arechaga

Jigsaw Sudoku, also known as Irregular Sudoku or geometric sudoku, is one of the most fun variants of classic sudoku. The rule that changes is easy to grasp but completely transforms the board: the usual 3x3 boxes are replaced with irregularly shaped regions. Here are the rules and tips to solve it.

What is Jigsaw Sudoku?

It's a 9x9 sudoku variant where the board is divided into 9 irregularly shaped regions (like puzzle pieces), each of 9 cells. Instead of the usual square 3x3 boxes, you get quirky-shaped regions marked with a thick border. The rest of the sudoku rules stay the same.

Rules and how to play step by step

1. 1 to 9 without repeats in each row.
2. 1 to 9 without repeats in each column.
3. 1 to 9 without repeats in each irregular region (the ones bounded by the thick border).
4. You start with some clue cells and fill in the rest with logic. Every puzzle has a unique solution.

Tips to solve Jigsaw Sudoku

• Watch the elongated regions: the ones stretching across several rows or columns share lots of restrictions and tend to fall first.
• Cells where several regions meet: a cell gets clues from its row, its column and its region. Corners of odd-shaped regions usually have very few candidates.
• Apply the single-gap rule: if a region is missing only one number, you already know which one goes there.
• Combine the irregular geometry with the classic elimination techniques: every number placed opens new deductions.

How it differs from regular sudoku

Compared to classic sudoku, Jigsaw forces you to "relearn" where the boxes are in every puzzle, because their shape changes. That makes it feel fresh and surprising. If you enjoy variants, you'll also enjoy Sudoku X (Diagonal Sudoku) and Killer Sudoku.