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.
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.
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 '<'.