Sudoku FlowSudoku variants: Killer, Jigsaw, Diagonal, Samurai and more
Updated 2026-10-05
Killer Sudoku
The grid is divided into cages, each with a target sum. The digits in a cage add up to that sum and never repeat inside it, on top of the usual Sudoku rules. Killer Sudoku combines Sudoku with ideas from Kakuro.
Sources: Wikipedia: Killer sudoku, Wikipedia: Sudoku
Jigsaw Sudoku
Also called irregular or nonomino Sudoku. The nine 3×3 boxes are replaced by nine irregular regions of nine cells each, and each region must hold 1 to 9.
Sources: Wikipedia: Sudoku
Diagonal Sudoku (Sudoku X)
The two main diagonals of the grid must also contain each digit once, which gives the solver two more units to work with.
Sources: Wikipedia: Sudoku
Samurai Sudoku
Five 9×9 grids overlap at their corner boxes in the pattern of a five on a die. In Japan this layout is known as Gattai 5, five merged Sudoku.
Sources: Wikipedia: Sudoku
Bigger and smaller grids
Dell Magazines publishes 16×16 puzzles called Number Place Challenger, with the numbers 1 to 16 or the letters A to P. At the other end, a 6×6 Mini Sudoku with boxes of 3×2 appears in the American newspaper USA Today. There are 288 different finished 4×4 grids and 28,200,960 finished 6×6 grids with 2×3 boxes.
Sources: Wikipedia: Sudoku, OEIS A291187: number of 2×n Sudoku grids
