Fortress (chess)
In chess, the fortress is an endgame drawing technique in which the side behind in material sets up a zone of protection around their king that cannot be penetrated by the opponent. This only works when the opponent does not have a passed pawn or cannot create one, unless that pawn can be stopped (e.g. see the opposite-colored bishops example). An elementary fortress is a theoretically drawn (i.e. a book draw) position with reduced material in which a passive defense will maintain the draw (Müller & Pajeken 2008:183).
Fortresses commonly have four characteristics:
- Useful pawn breakthroughs are not possible
- If the stronger side has pawns, they are firmly blocked
- The stronger side's king cannot penetrate, either because it is cut off or near the edge of the board
- Zugzwang positions cannot be forced, because the defender has waiting moves available (de la Villa 2008:23).
Fortresses pose a problem for computer chess: computers are unable to reason about fortress-type positions except to the extent that their endgame tablebase allows.
Read more about Fortress (chess): Fortress in A Corner, Rook and Pawn Versus Queen, Opposite-colored Bishops, Queen Versus Two Minor Pieces, Knight Versus A Rook and Pawn, Bishop Versus Rook and Bishop Pawn On The Sixth Rank, Defense Perimeter (pawn Fortress), A Semi-fortress, Positional Draw
Famous quotes containing the word fortress:
“He began therefore to invest the fortress of my heart by a circumvallation of distant bows and respectful looks; he then entrenched his forces in the deep caution of never uttering an unguarded word or syllable. His designs being yet covered, he played off from several quarters a large battery of compliments. But here he found a repulse from the enemy by an absolute rejection of such fulsome praise, and this forced him back again close into his former trenches.”
—Sarah Fielding (1710–1768)