Candidate Passed Pawn
| Candidate passed pawn,
a pawn on a half-open file, which, if the board had only pawns on it, would eventually become a passed pawn by moving forward. Whereas this definition is obvious for a human, in a form presented above it would require no less than a separate recursive search routine. For that reason, computers have to use approximations of that rule.
One possibility is to define a pawn as a candidate, if no square on its path is controlled by more enemy pawns than own pawns. However, this simple heuristics rules out an early recognition of a candidate passed pawns. For example with white pawns on a4 and b5 and black pawn on a7, the b5 pawn would be viewed as a candidate passer only after a4-a5.
|White and Black candidates (b5, g5)|
- How to define a candidate passer by Jan Willem de Kort, CCC, January 03, 2006
- Outside passer and candidate passer: definition wanted! :-) by Alessandro Scotti, CCC, February 27, 2006
- Improving evaluation of passed pawns by Ben-Hur Carlos Vieira Langoni Junior, CCC, January 22, 2011 » Passed Pawn
- Pawn Power in Chess by Hans Kmoch - Glossary of Terms - Chess Forums - Chess.com 
- Candidates Tournament from Wikipedia
- Hans Kmoch (1959, 1990). Pawn Power in Chess. New York: Dover, 1990. Previous ed.: New York: McKay, 1959. ISBN 0-486-26486-6