Block (chess)

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Black to move. Her queen is under attack by the rook. It cannot capture the rook as it is protected by the bishop. If it moves aside then the White rook can capture the Black one, leading to back rank mate. By moving the knight to the e4, however, Black can block the rook's attack.

A block is a defensive tactic in chess in response to an attack, consisting of interposing a piece between the opponent's attacking piece and the piece being attacked. This type of blocking will only work if the attacking piece is a type that can move linearly an indefinite number of squares such as a queen, rook, or bishop and there is at least one empty square in the line between the attacking and attacked piece. Blocking is not an option when the attacking piece is directly adjacent to the piece it is attacking, or when the attacking piece is a knight (because knights "jump over other pieces" and cannot be blocked). When an opponent's attack on a piece is blocked, the blocking piece is to some extent pinned, either relatively or absolutely, until a future move by either side allows it to be unpinned.

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A check on a king by an opponent's queen, rook, or bishop can sometimes be blocked by moving a piece to a square in line in between the opponent's checking piece and the checked king. The blocking piece is then absolutely pinned to the king by the attacking piece.

Another type of interposing in chess can involve placing a piece between two opponent's pieces where one of those pieces is protecting the other, or they are both protecting each other. This chess tactic can be called interference .

Blocking and initiative

When the attack cannot be ignored, the attacking player has the initiative. The defending player may be able to acquire the initiative by blocking and attacking at the same time, by attacking an undefended attacker with the blocking piece, with a discovered attack, or when the block is also a check or a cross-check.

See also

Related Research Articles

Chess strategy is the aspect of chess play concerned with evaluation of chess positions and setting of goals and long-term plans for future play. While evaluating a position strategically, a player must take into account such factors as the relative value of the pieces on the board, pawn structure, king safety, position of pieces, and control of key squares and groups of squares. Chess strategy is distinguished from chess tactics, which is the aspect of play concerned with the move-by-move setting up of threats and defenses. Some authors distinguish static strategic imbalances, which tend to persist for many moves, from dynamic imbalances, which are temporary. This distinction affects the immediacy with which a sought-after plan should take effect. Until players reach the skill level of "master", chess tactics tend to ultimately decide the outcomes of games more often than strategy does. Many chess coaches thus emphasize the study of tactics as the most efficient way to improve one's results in serious chess play.

King (chess) Chess piece

The king is the most important piece in the game of chess. In algebraic notation, the king is abbreviated in English by the letter K. If a player's king is threatened with capture, it is said to be in check, and the player must remove the threat of capture on the next move. If this cannot be done, the king is said to be in checkmate, resulting in a loss for that player. Players cannot make any move that places their own king in check. Although the king is the most important piece, it is one of the weakest pieces in the game outside of the endgame.

Chess piece Game piece for playing chess

A chess piece, or chessman, is any of the six different types of movable objects used on a chessboard to play the game of chess.

In chess, a pin is a chess tactic in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece. Moving the attacking piece to bring on the pin is called pinning; the defending piece so restricted is described as pinned. Only pieces that can move an indefinite number of squares in a horizontal, vertical, or diagonal line can pin. Kings, knights, and pawns cannot pin. Any piece can be pinned except the king, since the king must be immediately removed from check under all circumstances. It is like a skewer, but in a skewer, the more valuable piece is the one under direct attack.

Rules of chess Rules of play for the game of chess

The rules of chess are rules governing the play of the game of chess. While the exact origins of chess are unclear, modern rules first took form during the Middle Ages. The rules continued to be slightly modified until the early 19th century, when they reached essentially their current form. The rules also varied somewhat from place to place. Today, the standard rules are set by FIDE, the international governing body for chess. Slight modifications are made by some national organizations for their own purposes. There are variations of the rules for fast chess, correspondence chess, online chess, and Chess960.

This glossary of chess explains commonly used terms in chess, in alphabetical order. Some of these terms have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of named opening lines, see List of chess openings; for a list of chess-related games, see List of chess variants.

Alice chess Chess variant played on two boards

Alice chess is a chess variant invented in 1953 by V. R. Parton which employs two chessboards rather than one, and a slight alteration to the standard rules of chess. The game is named after the main character "Alice" in Lewis Carroll's work Through the Looking-Glass, where transport through the mirror into an alternate world is portrayed on the chessboards by the after-move transfer of chess pieces between boards A and B.

A fairy chess piece, variant chess piece, unorthodox chess piece, or heterodox chess piece is a chess piece not used in conventional chess but incorporated into certain chess variants and some chess problems. Compared to conventional pieces, fairy pieces vary mostly in the way they move, but they may also follow special rules for capturing, promotions, etc. Because of the distributed and uncoordinated nature of unorthodox chess development, the same piece can have different names, and different pieces the same name in various contexts. Most are symbolised as inverted or rotated icons of the standard pieces in diagrams, and the meanings of these "wildcards" must be defined in each context separately. Pieces invented for use in chess variants rather than problems sometimes instead have special icons designed for them, but with some exceptions, many of these are not used beyond the individual games for which they were invented.

Madrasi chess is a chess variant invented in 1979 by Abdul Jabbar Karwatkar. The game uses the conventional rules of chess with the addition that when a piece is attacked by a piece of the same type but opposite colour it is paralysed and becomes unable to move, capture or give check.

Interference (chess)

In the game of chess, 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 present a threat. Huczek defines interference as a tactic involving blocking moves that obstruct lines of attack. This definition may be expanded by including blocking moves that disrupt lines of defense.

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.

Luft

In chess, luft designates the space or square left by a pawn move into which a king may then retreat, especially such a space made intentionally to avoid back-rank checkmate. A move leaving such a space is often said to "give the king some luft". The term "luft", "lufting", or "lufted" may also be used to refer to the movement of the relevant pawn creating luft.

Check (chess) Chess condition in which the King is attacked

A check is a condition in chess, shogi, xiangqi, and janggi that occurs when a player's king is under threat of capture on their opponent's next turn. A king so threatened is said to be in check. A player must get out of check, if possible, by interposing a piece between the threatening piece and the king, capturing the threatening piece, or moving the king to a square where it is no longer in check. If the player cannot get out of check by any of these options on their next move, the game ends in checkmate and the player loses. Players cannot make any move that puts their own king in check.

Isolated pawn

In chess, an isolated pawn is a pawn that has no friendly pawn on an adjacent file. Isolated pawns are usually a weakness because they cannot be protected by other pawns. The square in front of the pawn may become a good outpost or otherwise a good square for the opponent to anchor pieces. Isolated pawns most often become weaker in the endgame, as there are fewer pieces available to protect the pawn.

In the tactics and strategy in the board game of chess, an exchange or trade of chess pieces is a series of closely related moves, typically sequential, in which the two players capture each other's pieces. Any types of pieces except the kings may possibly be exchanged, i.e. captured in an exchange, although a king can capture an opponent's piece. Either the player of the white or the black pieces may make the first capture of the other player's piece in an exchange, followed by the other player capturing a piece of the first player, often referred to as a recapture. Commonly, the word "exchange" is used when the pieces exchanged are of the same type or of about equal value, which is an even exchange. According to chess tactics, a bishop and a knight are usually of about equal value. If the values of the pieces exchanged are not equal, then the player who captures the higher-valued piece can be said to be up the exchange or wins the exchange, while the opponent who captures the lower-valued piece is down the exchange or loses the exchange. Exchanges occur very frequently in chess, in almost every game and usually multiple times per game. Exchanges are often related to the tactics or strategy in a chess game, but often simply occur over the course of a game.

Omega Chess is a commercial chess variant designed by Daniel MacDonald. The game is played on a 10×10 board with four extra squares, each added diagonally adjacent to the corner squares. The game is laid out like standard chess with the addition of a champion in each corner of the 10×10 board and a wizard in each new added corner square.

Checkmate pattern Chess patterns

In chess, several checkmate patterns occur frequently enough to have acquired specific names in chess commentary. The diagrams that follow show these checkmates with White checkmating Black.

In chess, a skewer is an attack upon two pieces in a line and is similar to a pin. A skewer is sometimes described as a "reverse pin"; the difference is that in a skewer, the more valuable piece is the one under direct attack. The opponent is compelled to move the more valuable piece to avoid its capture, thereby exposing the less valuable piece which can then be captured. Only line pieces can skewer; kings, knights, and pawns cannot.

Outline of chess Overview of and topical guide to chess

The following outline is provided as an overview of and topical guide to chess:

Many basic tactics of shogi are similar to those of chess tactics, involving forks, pins, removing the defender and other techniques, all of which are considered very strong when used effectively.

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