Interference (chess)
Encyclopedia
Interference occurs when the line between an attacked piece and its defender is interrupted by sacrificially interposing a piece. It is a chess
tactic
which seldom arises, and is therefore often overlooked. Opportunities for interference are rare because the defended object must be more valuable than the sacrificed piece, and the interposition must itself represent a threat.
In the position at left, White to play will apparently be obliged to retreat the knight from f5, because the squares to which it could advance are all guarded. However, the interference move 1.Nd6+ interrupts the black rook's defense of the black queen. If Black plays either 1...cxd6 or 1...Bxd6, White will capture Black's queen. Therefore Black has no better play than 1...Rxd6 2.exd6 Qxe2 3. Rxe2 Bxd6, conceding the exchange for a pawn.
A more subtle example of interference occurs when the interposing piece interrupts two lines simultaneously. In this case, the moving piece does not have to pose a threat by itself. Instead, it makes the opponent trip over his own feet, so to speak, because capturing the offending piece will necessarily break one line of defense or the other.
In the position at right, White is at a material disadvantage, and apparently can't queen the a-pawn because the black bishop guards the queening square. However, 1.Nd5 interferes with the bishop and with the black rooks' defense of each other. If 1...Bxd5, 2.Rxd8 is crushing. Also, if 1. Nd5 is answered by 1...R8xd5, it would allow Rh8 mate. The best Black can do is 1...R2xd5, interfering with the bishop's guard of a8 and allowing 2.a8Q.
Although interferences are quite rare in actual play, they are a common theme in chess problem
s. The device in the last example above, in which a sacrifice occurs on the intersection of the defensive lines of two differently moving pieces, is known to problemists as a Novotny. Various other types of interference are given specific names in problem terminology
, including the Grimshaw
, Plachutta
where the two pieces both move orthogonally (see a beautiful example by Tarrasch), Anti-Bristol, Holzhausen
and Wurzburg-Plachutta.
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...
tactic
Chess tactic
In chess, a tactic refers to a sequence of moves which limits the opponent's options and may result in tangible gain. Tactics are usually contrasted with strategy, in which advantages take longer to be realized, and the opponent is less constrained in responding.The fundamental building blocks of...
which seldom arises, and is therefore often overlooked. Opportunities for interference are rare because the defended object must be more valuable than the sacrificed piece, and the interposition must itself represent a threat.
In the position at left, White to play will apparently be obliged to retreat the knight from f5, because the squares to which it could advance are all guarded. However, the interference move 1.Nd6+ interrupts the black rook's defense of the black queen. If Black plays either 1...cxd6 or 1...Bxd6, White will capture Black's queen. Therefore Black has no better play than 1...Rxd6 2.exd6 Qxe2 3. Rxe2 Bxd6, conceding the exchange for a pawn.
A more subtle example of interference occurs when the interposing piece interrupts two lines simultaneously. In this case, the moving piece does not have to pose a threat by itself. Instead, it makes the opponent trip over his own feet, so to speak, because capturing the offending piece will necessarily break one line of defense or the other.
In the position at right, White is at a material disadvantage, and apparently can't queen the a-pawn because the black bishop guards the queening square. However, 1.Nd5 interferes with the bishop and with the black rooks' defense of each other. If 1...Bxd5, 2.Rxd8 is crushing. Also, if 1. Nd5 is answered by 1...R8xd5, it would allow Rh8 mate. The best Black can do is 1...R2xd5, interfering with the bishop's guard of a8 and allowing 2.a8Q.
Although interferences are quite rare in actual play, they are a common theme in chess problem
Chess problem
A chess problem, also called a chess composition, is a puzzle set by somebody using chess pieces on a chess board, that presents the solver with a particular task to be achieved. For instance, a position might be given with the instruction that White is to move first, and checkmate Black in two...
s. The device in the last example above, in which a sacrifice occurs on the intersection of the defensive lines of two differently moving pieces, is known to problemists as a Novotny. Various other types of interference are given specific names in problem terminology
Chess problem terminology
This is a list of terms used in chess problems. For a list of unorthodox pieces used in chess problems, see fairy chess piece. For a list of terms used in chess is general, see chess terminology.- A :*Actual play - see post-key play....
, including the Grimshaw
Grimshaw (chess)
A Grimshaw is a device found in chess problems in which two black pieces arriving on a particular square mutually interfere with each other. It is named after the 19th century problem composer Walter Grimshaw....
, Plachutta
Plachutta
The Plachutta is a device found in chess problems: a white piece sacrifices itself on a square where it could be captured by one of two similarly-moving black pieces moving along a different line; whichever black piece captures, it interferes with the other...
where the two pieces both move orthogonally (see a beautiful example by Tarrasch), Anti-Bristol, Holzhausen
Holzhausen
Holzhausen may refer to:Places*in Germany:**Holzhausen, Saxony-Anhalt, a municipality in the district of Stendal, Saxony-Anhalt**Holzhausen an der Haide, a municipality in the Rhein-Lahn district, Rhineland-Palatinate...
and Wurzburg-Plachutta.