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 tactics are move sequences in which the opponent is unable to respond to all threats, so the first player realizes an advantage. This includes forks, skewers, batteries, discovered attacks, undermining, overloading, deflection, pins and interference.

• The Encyclopedia of Chess Middlegames gives the following tactical categories: Double Attack, Pawns Breakthrough, Blockade, Decoying, Discovered Attack, Passed Pawn, X-ray Attack, Interception, Deflection, Pin, Demolition of Pawns, Overloading, Annihilation of Defense, Pursuit (perpetual attack), Intermediate Move, and Space Clearance.

Often tactics of several types are conjoined in a combination.

Attacking and defending pieces

A piece is said to attack (or threaten) an opponent's piece if, in the next move, it could capture that piece. A piece is said to defend (or protect) a piece of the defender's color if, in case the defended piece were taken by the opponent, the defender could recapture right away. Attacking a piece usually, but not always (see sacrifice), forces the opponent to respond if the attacked piece is undefended, or if the attacking piece is of lower value than the attacked one.

When attacked, one has several options:

• Capture the attacking piece.
• Move the attacked piece.
• Interpose another piece in between the two, if the attacker is not a knight and is not directly adjacent to the piece attacked.
• Guard the attacked piece and permit an exchange.
• Pin the attacking piece so the capture becomes illegal or unprofitable.
• Use a zwischenzug (create a counter-threat).

Gaining material

When one player is able to capture an opponent's piece or pieces without losing any of his own, that player is said to have won material; that is, the opponent will have fewer pieces on the board. The goal of each basic tactic is to win material. At the professional level, often the mere threat of material loss (i.e., an anticipated tactic) induces a player to pursue an alternative line. In amateur games, however, tactics often come to full fruition, as they are not foreseen by the opponent and so result in material gain and a corresponding, perhaps decisive, advantage. Material gain can be accomplished by several different types of tactics.

Discovered attack

Main article: Discovered attack

A discovered attack is a move which allows an attack by another piece. A piece is moved away so as to allow the attack of a friendly bishop, rook or queen on an enemy piece. If the attacked piece is the king, the situation is referred to as a discovered check. Discovered attacks are powerful as the moving piece may be able to pose a second threat.

A special case of a discovered check is a double check, where the piece being unmasked and the piece being moved attack the enemy king. A double check requires that the opponent moves his/her king as the king is under attack from two directions and it is impossible to counter both at the same time in any other way.

Animated example of a Discovered Attack	Animated example of a Discovered Check

Fork

Main article: Fork

Garry Kasparov vs. World Team 1999

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Kasparov played 12.Nc7+, which forks black's king and rook on a8.

A fork is a move that uses one piece to attack two or more of the opponent's pieces simultaneously, hoping to achieve material advantage, since the opponent can only counter one of the two threats. Knights are often used for forks, with their unique moving and jumping ability. A common situation is a knight jumping to c2 or c7, thereby threatening both the enemy rook and the king. Such "king forks" are particularly effective, because the opponent is forced by the rules of the game to alleviate the threat to the king. The opponent cannot choose to defend the other piece, and thus cannot use a zwischenzug to complicate the situation. Pawns can also be effective for forking. By moving a pawn forward, it may attack two pieces; one diagonally to the left and one diagonally to the right.

Queens are also excellent forking pieces, because they can move in eight different directions. However, this is only useful if both pieces are undefended, or if one is undefended and the other is the opposing king. The queen is the most valuable piece (excluding the king), so it is usually not profitable for it to capture a defended piece.

Fork attacks can be either 'Relative', which is when the attacked units are any of the Pawns, Knights, Bishops, Rooks, or Queen(s). Or, the Fork attacks can be 'Absolute', which is when one of the attacked pieces includes the King.

Animated example of a Relative Fork Attack	Animated example of an Absolute Fork Attack

Pin

Paul Morphy vs. Consultation Team 1858

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After Morphy's 14th move, both Black's knight and rook on d7 are pinned.

Main article: Pin

A pin is a move which forces one of the opponent's pieces to stay put because moving it would expose a more valuable piece behind it. Sometimes pinned pieces cannot move at all, as doing so would expose the king. Only bishops, rooks, and queens can pin other pieces, because they can move more than one square in a straight line.

Pin attacks can be either 'Relative' or 'Absolute', as shown by the two animated images, below. The Absolute Pin is where the more valuable piece behind is the King (this is the distinguishing feature between Absolute and Relative Pins).

Animated example of a Relative Pin Attack	Animated example of an Absolute Pin Attack

Skewer

Main article: Skewer

A skewer is a move which attacks two pieces in a line, similar to a pin, except that the enemy piece of greater value is in front of the piece of lesser value. After the more valuable piece moves away, the lesser piece can be captured. Queens, rooks, and bishops can perform the skewer.

Skewer attacks can be either 'Relative' or 'Absolute', as shown by the two animated images, below. The Absolute Skewer is where the more valuable piece in front is the King (this is the distinguishing feature between Absolute and Relative Skewers).

With Absolute Skewers, because it's the King that's attacked, the King is in Check and, unless the attacker can be dealt with (by capture, or by blocking the Check with a Pawn or another Piece), the attacked King will have to step aside, allowing the attacking unit to capture the less valuable Pawn or Piece behind.

If the attacked unit wasn't the King - say, a Rook - then it would be a Relative Skewer and should the situation require it, the Rook 'could' remain in place, at risk of being captured, for the sake of protecting whatever unit is behind.

Animated example of a Relative Skewer Attack	Animated example of an Absolute Skewer Attack

Pawns

Pawns are extremely useful in the game and are far more powerful than meets the eye. For instance, since pawns are the least valuable chess piece, they can be used to capture defended pieces. A single pawn approaching will force a more powerful piece, such as a rook or a knight, to retreat. A simple move of a pawn may reveal a hidden threat (see Discovered attacks). Also, when pawns are arranged in a diagonal line, with the frontmost pawns guarded by the pawns behind, they form an almost impenetrable wall capable of protecting any pieces directly behind them. A weak pawn structure, with unprotected, isolated pawns ahead of more valuable pieces, can be a decisive weakness. Furthermore, a pawn which has progressed all the way to the opposite side of the board may be promoted to any other piece except a king.

Sacrifices

Colle vs. O'Hanlon 1930

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Colle played 12.Bxh7+, an example of the so-called Greek gift sacrifice.

Main article: Sacrifice

Sacrificing some material is often necessary to throw the opponent's position out of balance, potentially gaining positional advantage. The sacrificed material is sometimes later offset with a consequent material gain. Pawn sacrifices in the opening are known as gambits; they are usually not intended for material gain, but rather to achieve a more active position.

Direct attacks against the enemy king are often started by sacrifices. A common example is sacrificing a bishop on h2 or h7, checking the king, who usually must take the bishop. This allows the queen and knight to develop a fulminant attack.

Zugzwang

Main article: Zugzwang

Zugzwang (German for compulsion to move) occurs when a player is forced to make an undesirable move. The player is put at a disadvantage because he would prefer to pass and make no move, but a move has to be made, all of which weaken his position. Situations involving zugzwang occur uncommonly, but when they do occur, it is almost always in the endgame, where there are fewer choices of available moves.

Zwischenzug

Main article: Zwischenzug

Zwischenzug (German for intermediate move) is a common tactic in which a player under threat, instead of directly countering, introduces an even more devastating threat. The tactic often involves a new attack against the opponent's queen or king. The opponent then may be forced to address the new threat, abandoning the earlier attack.

The concept of a zwischenzug is often listed as a tactic, but might properly be called a counter-tactic instead. The effect of a zwischenzug is to change the status quo before a tactic can come to fruition. The near ubiquity of the zwischenzug makes long combinations all the more rare and impressive.

See also

• Outline of chess: Chess tactics
• Chess strategy
• Pawn structure
• Tempo (chess)
• Triangulation (chess)

Further reading

• Yasser Seirawan (2005), Winning Chess Tactics, Everyman Chess, ISBN 1-85744-385-3 

External links

• Predator at the Chessboard - A Field Guide to Chess Tactics - Learn chess tactics
• Tactics technical paper suite
• Chessity -- gaming your training
• ChessGYM - Tactical chess problems
• Chess Tactics Server - Tactical chess problems
• Chess Tempo - Tactical chess problems
• Chess Tactics Repository - Tactical chess problems
• Adaptive Tactics Server -- Tactical chess problems
• Practice your tactics by playing -- Get together with other players
• IdeaChess -- Tactical chess problems
• Chess Tactics Videos -- Includes video clips of 15 different Chess Tactics