Killer Sudoku
Background
Despite its similarity to CalcuDoku, killer sudoku precedes it by a decade, having been developed in Japan and first appearing in the English-speaking world around 2005.
Puzzle and Goal
An unsolved puzzle consists of a basic sudoku grid (usually 9x9) with areas marked off. Each area contains a small numeric clue, while the normal sudoku clues are absent.
The goal is to fill the cells with a Latin square.
Rules
The solved grid must satisfy the following conditions:
The sum of the numbers in each area (or "cage") is equal to the clue provided.
The same digit cannot appear twice in any area or region.
Variants
In Gebietssummen, you can have the same digit twice in the same region.
Other Names
Addoku; Gebietssumme; Kikagaku Nampure; Samunamupure; Sum Number Place; Sum Sudoku; Sumdoku
Playable Online