Killer Sudoku

Killer Sudoku (aka Addoku and Sumdoku) is a happy conjunction of Sudoku and Kakuro, making it a puzzle that requires both logic and mathematical ability to solve. The normal sudoku rules apply (each row, each column and each 3×3 block must contain the numbers 1 to 9), but the grid is overlaid with an irregular mosaic of cages, marked by dotted lines. The sum of the numbers placed in each cage must equal the small number clue in the top corner of the cage. No number can be repeated within a cage.

The strategies that are employed to solve sudoku and Kakuro can be used for this puzzle, separately and in combination. Particularly helpful to the solver is the 45 principle – the fact that 1 to 9 must fit in a row, column or 3×3 block means that the sum of numbers in each must equal 45 (1+2+3 etc). 

We can create killer sudoku at different levels of difficulty to suit the audience.