Rook on Open File

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Home * Evaluation * of Pieces * Rook on (Semi) Open Files

An open file is usually defined as a file with no pawns on it - a semi-open file as containing only the enemy pawns. In both cases a rook occupying such a file gets greater vertical mobility as well as a chance to penetrate the enemy camp, positioning itself on the 7th rank.

Early versions of Fruit omitted this evaluation term altogether. Some programs, like Rebel, have an additional bonus for doubling rooks on an open file. Some increase the bonus if the file has a bearing against the enemy king , some make the bonus dependent on the number of own pawns. It is worth noting that Nimzowitsch in My System used the term "(semi) open file" even for the rooks standing in front of the pawn chain. The same has been said about Rybka. Bonuses applied to a rook on an open file vary from 8 to 20 centipawns [1]. Typical bonus for a semi-open file is half of that for a fully open file.

See also

Forum Posts


  1. 20 cp comes from Toga log user manual, after adding actual bonus and penalty for a rook on a closed file

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