How to play Killer Sudoku
Killer Sudoku combines classic Sudoku rules with outlined cages. The digits inside each cage must add up to its small target total.
Play Killer SudokuKiller Sudoku rules
- Use digits 1 to 9 once in every row, column and 3×3 box.
- The digits in each dotted cage must equal its target sum.
- A digit cannot repeat inside a cage.
The 45 rule
Every complete row, column and 3×3 box contains 1 through 9, which total 45. Comparing cage totals with 45 can reveal the value of squares that cross a boundary.
Start with constrained cages
Single-square cages are fixed immediately. Small cages with low or high totals also have fewer possible combinations, making them useful starting points.