Killer Sudoku Strategy Guide

Key Strategies

1. 01

   Use cage sums like kakuro

   Each cage's sum constrains which digits can appear in it. A 2-cell cage summing to 3 must contain {1,2}. Memorize unique-sum combinations for small cages.

2. 02

   Apply standard sudoku rules too

   Killer Sudoku is still Sudoku — every row, column, and 3×3 box must contain 1–9 with no repeats. Use all standard Sudoku techniques alongside cage logic.

3. 03

   45 rule for rows, columns, and boxes

   Every row, column, and box sums to 45. If a group of cages fits entirely within a row/column/box, and one cage straddles the boundary, you can calculate the straddling cage's contribution.

4. 04

   Eliminate digits using cage overlap

   If two cells in a cage must together contain specific digits, those digits are used up within the cage and cannot appear again in their shared row, column, or box.