Killer Sudoku Rules

Summary

The rules for Killer Sudoku are simple. The rules for regular sudoku apply, with one additional rule: The sum of the cells in a cage must equal the total given for the cage. Each digit in the cage must be unique.

Terminology

Cell A single box. It can contain any digit from one to nine.
Row A horizontal group of nine cells. Each cell in the row must contain a different digit.
Column A vertical group of nine cells. Each cell in the column must contain a different digit.
Nonet A 3x3 grid of cells. It is surrounded by bold lines. Each cell in the nonent must contain a different digit.
Cage A group of cells surrounded by a dashed line. The values of the cells in a cage must sum up to the total specified in the upper right of the cage.

The values in a cage must be unique even if the rules of regular sudoku would allow for duplicates. For example, the cells labeled 'a' and 'b' in the figure cannot have the same value.

Region An area of the puzzle that cannot contain duplicate digits. That is, a row, a column, a nonet, or a cage.

Rules

As in regular sudoku, every cell in each row, column, and nonet must contain a unique digit. In other words, each row, column, and nonet must contain all the digits from one to nine.

The values of the cells a cage must sum up to the total for that cage.

The values of the cells in a cage must be unique.

Rules for Greater Than Killer Sudoku

The rules for Killer Sudoku apply. If there is a '>', '<', or, '=' between to cages, then the sum of the values in the cages must obey the relationship specified.

Rules for Greater Than Sudoku

The rules for regular sudoku apply. The values of each cell must obey the relationship between the cells specified with '>' or '<'.