Candidate

A candidate value, usually called simply a candidate, represents a digit that can be placed into an unsolved cell. Another word used is possibility.

Players often use pencilmarks to write the remaining candidates in the grid. Sudoku computer programs also provide markup tools to show the remaining candidates.

When a solving technique proves that a candidate is no longer valid, this candidate is subsequently eliminated. When a Sudoku is completely solved, all candidates are either eliminated or placed in their respective cells.