Best SudokuKiller Sudoku
Killer Sudoku takes a normal Sudoku grid and adds cages: groups of cells outlined with a dotted line, each with a small number in the corner. That number is the total of the digits in the cage, and a digit can’t repeat inside a cage. Most Killer puzzles show few or no starting digits, so the sums do the work.
The rules
- Fill the grid so every row, column and 3×3 box holds 1 to 9.
- The small number in a dotted cage is the sum of that cage.
- A number can’t repeat inside a cage.
An example puzzle
An Easy Killer Sudoku puzzle with 10 starting digits. It has one solution.
Cage combinations that fit only one way
Some totals can be made from digits in only one way. Learn these and many cages solve themselves.
| Cage size | Sum | Digits |
|---|---|---|
| 2 cells | 3 | 1 and 2 |
| 2 cells | 4 | 1 and 3 |
| 2 cells | 16 | 7 and 9 |
| 2 cells | 17 | 8 and 9 |
| 3 cells | 6 | 1, 2 and 3 |
| 3 cells | 7 | 1, 2 and 4 |
| 3 cells | 23 | 6, 8 and 9 |
| 3 cells | 24 | 7, 8 and 9 |
| 4 cells | 10 | 1, 2, 3 and 4 |
| 4 cells | 11 | 1, 2, 3 and 5 |
| 4 cells | 29 | 5, 7, 8 and 9 |
| 4 cells | 30 | 6, 7, 8 and 9 |
The 45 rule
Every row, column and box holds 1 to 9, so each one adds up to 45. If a few cages cover a whole row, column or box except for one or two cells, subtract their sums from 45. What’s left is the total of the missing cells, and one missing cell gives you its digit straight away.
How to start
- Fill in every cage whose sum has only one combination.
- Use notes to mark which digits each cage cell can still hold.
- Apply the 45 rule to rows, columns and boxes that are nearly covered by cages.
- Then solve like normal Sudoku: singles first, then pairs.
More ways to play
Print Killer Sudoku puzzles · All variants · Sudoku techniques