Chess tactics

In chess, a tactic refers to a sequence of moves that 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 tactics 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 more than one type are conjoined in a combination.

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 immediately recapture. 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 one attacked.

When the piece attacked is a king, then a player has exactly three options:

When the piece attacked is not a king, a player has more options:

When a player is able to capture the opponent's piece(s) without losing any of his own (or losing a piece of lesser value), the player is said to have "won material"; i.e., the opponent will have fewer (or less valuable) pieces remaining 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 the opponent to pursue an alternative line. In amateur games, however, tactics often come to full fruition – unforeseen by the opponent and resulting in material gain and a corresponding, perhaps decisive, advantage. Material gain can be achieved by several different types of tactics.

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Wikipedia