➕ Killer Sudoku
31 playsKiller Sudoku
Sudoku with few given digits or none at all — cages, and the sums they must reach.
About Killer Sudoku
The grid follows every ordinary sudoku law, yet starts with very little on it: nine digits on Easy, five on Medium, one on Hard and none at all on Expert. In place of the usual givens, dashed cages cover the board, each marked with the total its cells must reach, and no digit may repeat within a cage any more than within a row, column or box. Most of the work therefore starts from arithmetic: the cages whose totals admit only one set of digits, and the fact that every full row, column and box comes to forty-five. It is a stricter discipline than plain sudoku, and correspondingly more satisfying when a region falls.
How to Play
Select a cell and enter a digit; rows, columns and boxes each hold one to nine exactly once. Every dashed cage must add up to the small total printed in its corner, with no digit repeated inside the cage. Use notes to record candidates, and choose from four difficulty levels.
💡 Tips & Strategy
Every sudoku technique still applies, but cages give you a head start that ordinary sudoku lacks. Begin with the small cages of fixed composition: a pair adding to 3 can only be 1 and 2, a pair adding to 17 only 8 and 9, and three cells adding to 6 only 1, 2 and 3. These settle digits while most of the grid is still bare.
The rule of 45 is the tool that separates quick solves from slow ones. Every row, column and box holds each digit once, so each sums to 45. If the cages lying wholly inside a box total 38, the cells left over must total 7. Cages that straddle a boundary are handled the same way by subtracting the part you know.
Inside a cage no digit repeats, which quietly constrains more than it appears to. A three-cell cage summing to 7 must be 1+2+4 — not 1+3+3 — and that eliminates 3 from all three cells at a stroke.
Work boxes with dense small cages first. They resolve quickly, and each resolved cage feeds the ordinary row-and-column scanning that carries you through the rest of the grid.