Sudoku Glossary

Given: A pre-filled number in the starting puzzle.

Candidate: A possible number for an empty cell.

Single: A cell with exactly one valid candidate.

Hidden Single: A number that appears as a candidate in only one cell within a row, column, or box.

Naked Pair: Two cells in one unit sharing the same two candidates, allowing elimination elsewhere in that unit.

Naked Triple: Three cells in one unit containing only three shared candidates.

Box-Line Reduction: When candidates in a box align in one row/column, allowing eliminations outside the box.

X-Wing: A pattern across two rows and two columns that removes candidates.

Swordfish: A larger extension of X-Wing using three rows and columns.

Unique Solution: A puzzle should resolve to one valid final grid without guessing between multiple endings.