Glossary of Sudoku

This is a glossary of Sudoku terms and jargon. It is organized thematically, with links to references and example usage provided as ([1]). Sudoku with a 9×9 grid is assumed, unless otherwise noted.

A Sudoku (i.e. the puzzle) is a partially completed grid. A grid has 9 rows, 9 columns and 9 boxes, each having 9 cells (81 total). Boxes can also be called blocks or regions. Horizontally adjacent rows are a band, and vertically adjacent columns are a stack. The initially defined values are clues or givens. An ordinary Sudoku (i.e. a proper Sudoku) has one solution. Rows, columns and regions can be collectively referred to as groups, of which the grid has 27. The One Rule encapsulates the three prime rules, i.e. each digit (or number) can occur only once in each row, column, and box; and can be compactly stated as: "Each digit appears once in each group."

The classic 9×9 Sudoku format can be generalized to an

This accommodates variants by region size and shape, e.g. 6-cell rectangular regions. (N×N Sudoku is square). For prime N, polyomino-shaped regions can be used and the requirement to use equal-sized regions, or have the regions entirely cover the grid can be relaxed.

Other variations include additional value placement constraints, alternate symbols (e.g. letters), alternate mechanism for expressing the clues, and compositions with overlapping grids. See Sudoku – Variants for details and additional variants.

Sudokus variants can also have additional constraints on the placement of digits, such as "< >" relations, sums, linked cells, etc.

The meanings of most of these terms can be extended to region shapes other than boxes (square-shaped). To simplify reading, definitions are given only in terms of boxes.

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