| 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. |
