Guide
Sudoku Glossary: Every Term You Need to Know
Sudoku players have their own vocabulary. Here are the words you will meet most often, explained in plain language.
- Cell
- One of the 81 small squares in the grid.
- Row
- A line of nine cells from left to right.
- Column
- A line of nine cells from top to bottom.
- Box (block, region)
- One of the nine 3×3 squares outlined by thick lines.
- Unit
- Any row, column or box. Each unit must hold 1 to 9 once.
- Peers
- All the cells that share a row, column or box with a given cell. A cell has 20 peers.
- Given (clue)
- A number printed at the start of the puzzle.
- Candidate (pencil mark)
- A number that could still go in an empty cell. See pencil marks.
- Scanning (cross-hatching)
- Looking along rows and columns to find where a number must go. See scanning.
- Naked single
- A cell with only one candidate left.
- Hidden single
- A number that can go in only one cell of a unit.
- Naked pair
- Two cells in a unit with the same two candidates. Those numbers can be removed from the rest of the unit.
- Hidden pair
- Two numbers that can only go in the same two cells of a unit.
- Pointing pair
- When a number’s candidates in a box all lie in one row or column, it can be removed from that row or column outside the box.
- X-Wing
- A rectangle pattern of one candidate across two rows and two columns that lets you remove that candidate elsewhere.
- Unique solution
- A proper Sudoku has exactly one answer. See why.
Bookmark this page and come back whenever a guide uses a word you do not know.