Killer sudoku removes most givens and replaces them with dotted cages: digits in a cage must add to the small clue and cannot repeat inside that cage.
Normal sudoku row, column, and box rules still apply — cages add arithmetic constraints on top.
How to play Killer Sudoku
- Fill 1–9 in each row, column, and 3×3 box with no duplicates.
- Each dotted cage shows a target sum. Cells in that cage must add to the sum and cannot repeat a digit within the cage.
- No starting digits are shown — only cage sums. Use logic to find forced combinations.
- New game generates a fresh cage layout.
Strategy tips
- Start with two-cell cages: each sum has only a few possible pairs (e.g. 3 must be 1+2).
- Use box rules to eliminate pair candidates that would break a row or column.
- Large cages with unique combinations (only one way to hit the sum with distinct digits) are anchor points.
- If stuck, scan for a cage where only one digit fits after sudoku eliminations — not just cage math.
Common questions
Do I need to guess in Killer Sudoku?
Well-formed killer puzzles should be logic-only. If you are guessing, revisit small cages and box-line eliminations.
