Killer Sudoku

Decorative illustration of a caged Sudoku-style grid on parchment beside an abacus and red blossoms.

Killer Sudoku

Let the sums narrow the choices

Each row, column and 3×3 box still needs the digits 1–9 once. Outlined cages add two rules: their digits must reach the printed total without repeating. A valid placement must satisfy both the cage and the surrounding Sudoku grid.

01

Separate the set from its order

A two-cell cage totaling 17 contains 8 and 9. That identifies the pair; a row, column or box restriction must still determine their positions.

02

Check every cell in a cage

A combination survives only when its digits can fit the actual cells together. Check each possible assignment against row, column, box and cage restrictions.

03

Count the cells before subtracting

A row, column or box totals 45. Subtract only disjoint cages entirely inside it, and count every covered cell exactly once before finding the remainder.