How to Play Killer Sudoku

Killer Sudoku combines classic Sudoku logic with arithmetic cage constraints. The most challenging Sudoku variant.

Short rules

  1. Standard Sudoku: fill 1–9 in every row, column, and 3×3 box.
  2. Dashed cages group cells whose digits must sum to the shown total.
  3. No digit repeats within a cage.

How to Play

  • Calculate which digit combinations fit a cage's sum and size.
  • Cross-reference cage constraints with row/column uniqueness.
  • Work outward from cages that have the fewest digit possibilities.

Advanced rules

Try a short example

A few guided steps on the real board. Nothing here is scored.