How to play Killer Sudoku
Sudoku with a twist: the clues are sums, not starting digits.
The rules
- All the normal Sudoku rules apply: 1 to 9 once in every row, column and 3×3 box.
- Dashed outlines are cages. The small number in the corner is the total of the digits inside.
- A digit can't repeat inside a cage.
A quick example
Two different digits that make 3 can only be 1 and 2. Two that make 17 can only be 8 and 9.
Tips
- Learn the unique cages: 3 = 1+2, 4 = 1+3, 16 = 7+9, 17 = 8+9 for two squares; 6 = 1+2+3 and 24 = 7+8+9 for three.
- Every row, column and box adds up to 45. If all but one square of a box is covered by cages, the last square is 45 minus their totals.
- Notes are essential here. Auto-notes can fill in candidates for you.
- Combine cage sums with ordinary Sudoku scanning; the two work together.
Most puzzles take 10 to 30 minutes.
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