Check (board game) - AbsoluteAstronomy.com

In games such as chess

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...

, shogi

Shogi

, also known as Japanese chess, is a two-player board game in the same family as Western chess, chaturanga, and Chinese Xiangqi, and is the most popular of a family of chess variants native to Japan...

, and xiangqi

Xiangqi

Xiangqi is a two-player Chinese board game in the same family as Western chess, chaturanga, shogi, Indian chess and janggi. The present-day form of Xiangqi originated in China and is therefore commonly called Chinese chess in English. Xiangqi is one of the most popular board games in China...

, a check is the threat to capture the king

King (chess)

In chess, the king is the most important piece. The object of the game is to trap the opponent's king so that its escape is not possible . 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...

(or general in xiangqi) on the next turn to move. A king so threatened is said to be in check. In the following move, the player whose king is in check must get their king out of check, if it is possible. Either the threat must be stopped (by interposing a piece between the threatening piece and the king, or capturing the threatening piece) or the king must be moved to a space where it is no longer in check. If the player cannot get out of check, the game ends in checkmate

Checkmate

Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...

and the player loses. Announcing "check" is optional.

Introduction

A check is the result of a move that places the opposing king under an immediate threat by one (or sometimes two) of his pieces. (In some chess variant

Chess variant

A chess variant is a game related to, derived from or inspired by chess. The difference from chess might include one or more of the following:...

s, check by more than two pieces is possible.) If the king is in check and there is no legal move which gets the king out of check, the king is said to be checkmate

Checkmate

d and the game is over. The player whose king is checkmated loses and the opposing player wins the game.

It is against the rules

Rules 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...

for a player to make a move which puts or leaves their own king in check. Such a move is illegal and must be retracted (except under some variations of the rules for fast chess). A king cannot directly check the opposing king himself, since this would place the first king in check. (All other types of pieces can check.) A king can make a move which exposes the opposing king to a discovered check.

In this usage, the words "check" and "chess" come via Arabic from Persian shāh, meaning "king".

Getting out of check

There may be up to three possible ways to get a king out of a single check on the following move:

Capturing the checking piece, with either the king or another piece. If the checking piece is on a square next to the king, the king can capture the piece if the king does not move into a new check, i.e. if the piece is not protected by another enemy piece.
Moving the king to an adjacent square where it will not be in check. The king is not allowed to castle
Castling
Castling is a special move in the game of chess involving the king and either of the original rooks of the same color. It is the only move in chess in which a player moves two pieces at the same time. Castling consists of moving the king two squares towards a rook on the player's first rank, then...

when it is in check. The king may capture an enemy piece in a move to get out of check, as long as the piece is not protected.
Blocking the check. This will only work if the checking piece is a queen
Queen (chess)
The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

, rook
Rook (chess)
A rook is a piece in the strategy board game of chess. Formerly the piece was called the castle, tower, marquess, rector, and comes...

or bishop
Bishop (chess)
A bishop is a piece in the board game of chess. Each player begins the game with two bishops. One starts between the king's knight and the king, the other between the queen's knight and the queen...

and there is at least one empty square in the line between this checking piece and the checked king. Blocking a check is done by moving a piece (from the checked king's army) to a square in line in between the checking piece and the checked king. (The blocking piece is then absolutely pinned
Pin (chess)
In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

to the king by the attacking piece, until it is unpinned.) .

In the position in the first diagram, White can get out of check by three methods:

The move Nxa2, capturing the attacking piece
Moving the king to any unattacked square (marked with "x"), i.e. Kd6, Ke5, or Ke7.
Blocking the check by the move Rc4 or Nd5.

If a king is placed in double check

Double check

In chess, a double check is a check delivered by two pieces at the same time. In chess notation, it is often symbolized by "++".-Discussion:...

, the king must get out of both checks on the following move. Since it is impossible to capture both checking pieces or block both lines of attack in a single move, a double check can be escaped only by moving the king out of check. The king may, however, capture one of the checking pieces in the process, if that piece is adjacent to the king and not protected by another piece.

If none of these possibilities can get the king out of check, then it is checkmated and the game is lost by the player being checkmated.

Types of checks

A simple and very common type of check is when a piece moves to directly attack the opposing king only by itself. Sometimes such a check is part of a chess 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...

such as a fork

Fork (chess)

In chess, a fork is a tactic that uses a single piece to attack multiple pieces at the same time. The attacker usually hopes to gain material by capturing one of the opponent's pieces. The defender often finds himself in a difficult position in which he cannot counter all threats. The attacking...

, a skewer

Skewer (chess)

In chess, a skewer is an attack upon two pieces in a line and is similar to a pin. In fact, a skewer is sometimes described as a "reverse pin"; the difference is that in a skewer, the more valuable piece is in front of the piece of lesser or equal value...

, or a discovered attack

Discovered attack

In chess, a discovered attack is an attack revealed when one piece moves out of the way of another. Discovered attacks can be extremely powerful, as the piece moved can make a threat independently of the piece it reveals. Like many chess tactics, they succeed because the opponent is unable to meet...

on another piece. In some cases, a check can be used to defend against such tactics.

There are also a few more special types of check:

Discovered check - A discovered check is similar to any other type of discovered attack except that it is a discovered attack on the opposing king. In a discovered check, a piece moves out of the line of attack by another piece so that this other piece (which can be a queen, rook, or bishop) is then checking the opponent's king. The piece that actually moved in the discovered check move could possibly be any type of piece belonging to the same player as the checking piece except queen or the same type of piece administering the check. A discovered check could be a tactic in itself because the piece that moved could attack or otherwise create a threat to another piece on the checked king's side. The opponent has to get out of the discovered check on the following move and may not get a chance to thwart the attack by the other piece that moved.
Double check
Double check
In chess, a double check is a check delivered by two pieces at the same time. In chess notation, it is often symbolized by "++".-Discussion:...

- A double check is when two pieces check the opponent's king on the same checking move. This happens when the piece that moved during the checking move attacks the king and another piece checks by discovered check on the same move. It can also happen, though very rarely, when an en passant
En passant
En passant is a move in the board game of chess . It is a special pawn capture which can occur immediately after a player moves a pawn two squares forward from its starting position, and an enemy pawn could have captured it had it moved only one square forward...

capture opens two lines of attack simultaneously. In algebraic chess notation, a double check move is sometimes noted with a "++" after the written move in place of the usual "+", although "++" has been used to indicate checkmate (along with "#").

Cross-check
Cross-check
This article is about a type of move in chess. Cross checking is also a penalty in ice hockey.In chess, a cross-check is a tactic in which a check played in response to a check, especially when the original check is blocked by a piece that itself either delivers check or reveals a discovered check...

- In chess, when a check is answered by a check, particularly when this second check is delivered by a piece blocking the first, it is termed a cross-check
Cross-check
This article is about a type of move in chess. Cross checking is also a penalty in ice hockey.In chess, a cross-check is a tactic in which a check played in response to a check, especially when the original check is blocked by a piece that itself either delivers check or reveals a discovered check...

. In fact, a "cross-checkmate" is also possible in that way (that is, to answer a check with a checkmate) but since no such term exists, it would fall under the definition of cross-check as well. Cross-checks are rather rare but are a popular theme in chess problems.

Announcing check and notation

In friendly games, the checking player customarily says "check" when making a checking move. Announcing "check" is not required under the rules of chess

Rules of chess

and it is usually not done in formal games. Until the early 20th century a player was expected to announce "check", and some sources of rules even required it .

Less commonly (and obsolete), the warning garde can be said when a player directly attacks the opponent's queen

Queen (chess)

The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

in a similar way. This was mostly abandoned in the 19th century . The same move can be both check and garde simultaneously. Before the queen acquired its current move (about 1495) the rook was the most powerful piece. At that time the term check-rook was used for a move that checked the king and attacked a rook at the same time .

In algebraic chess notation

Algebraic chess notation

Algebraic notation is a method for recording and describing the moves in a game of chess. It is now standard among all chess organizations and most books, magazines, and newspapers...

, a checking move is recorded like any other move, except that a "+" is normally written after the move.

Checking in tactics and strategy

Sometimes checking an opponent provides no benefit to the checking player. This is called a "useless check" and it may even provide the checked opponent with a tempo

Tempo (chess)

In chess, tempo refers to a "turn" or single move. When a player achieves a desired result in one fewer move, he "gains a tempo" and conversely when he takes one more move than necessary he "loses a tempo"...

(move opportunity) to move his king into a safer position . For example, 1. e4 e6 2. d4 Bb4+? does nothing for Black and in fact causes him to lose a tempo after 3. c3!
A check given with the sole intention of delaying an inevitable defeat by one move is referred to as a "spite check", and may be considered somewhat unsporting .

However, there are many times when checking the opponent's king may be a useful tactic or part of a tactic, either in attacking or in defense. Checking is often used in combinations

Combination (chess)

In chess, a combination is a sequence of moves, often initiated by a sacrifice, which leaves the opponent few options and results in tangible gain. At most points in a chess game, each player has several reasonable options from which to choose, which makes it difficult to plan ahead except in...

with many other tactics or simply to force an opponent into a position where the opposing king can be checkmated, otherwise taken advantage of, or is otherwise worse for the opponent. Some attacks involves numerous checks to force an opponent into a losing position, especially when the king is exposed. An unexpected check in a forced combination or an overlooked cross-check in a planned series of checks may serve as sort of a zwischenzug

Zwischenzug

The zwischenzug is a chess tactic in which a player, instead of playing the expected move first interpolates another move, posing an immediate threat that the opponent must answer, then plays the expected move...

, foiling the plan.

Some uses of checking:

Repetitive checking to prevent losing a game going poorly (to draw
Draw (chess)
In chess, a draw is when a game ends in a tie. It is one of the possible outcomes of a game, along with a win for White and a win for Black . Usually, in tournaments a draw is worth a half point to each player, while a win is worth one point to the victor and none to the loser.For the most part,...

the game by perpetual check
Perpetual check
In the game of chess, perpetual check is a situation in which one player can force a draw by an unending series of checks. Such a situation typically arises when the player who is checking cannot deliver checkmate; while failing to continue the series of checks gives the opponent at least a chance...

)
Royal fork
Fork (chess)
In chess, a fork is a tactic that uses a single piece to attack multiple pieces at the same time. The attacker usually hopes to gain material by capturing one of the opponent's pieces. The defender often finds himself in a difficult position in which he cannot counter all threats. The attacking...

(knight
Knight (chess)
The knight is a piece in the game of chess, representing a knight . It is normally represented by a horse's head and neck. Each player starts with two knights, which begin on the row closest to the player, one square from the corner...

fork of king and queen) or other forks involving the king.
Checks to force an exchange.
A double check could be especially bad for the opponent since there are likely to be fewer options to get out of check. A double check is often more likely to lead to checkmate or loss of material.
A check might force a king to move so that it cannot castle
Castling
Castling is a special move in the game of chess involving the king and either of the original rooks of the same color. It is the only move in chess in which a player moves two pieces at the same time. Castling consists of moving the king two squares towards a rook on the player's first rank, then...

later.
Moving a piece to give check can sometimes open a line of attack on another piece. The opponent must escape the check, and therefore cannot (in general) prevent the other piece from being captured (discovered attack
Discovered attack
In chess, a discovered attack is an attack revealed when one piece moves out of the way of another. Discovered attacks can be extremely powerful, as the piece moved can make a threat independently of the piece it reveals. Like many chess tactics, they succeed because the opponent is unable to meet...

).
Similarly, the piece moved to create a discovered check may attack another enemy piece, leading to the same scenario.
The king may also, by being forced to move out of check, enable the checking piece to capture another piece (an absolute skewer
Skewer (chess)
In chess, a skewer is an attack upon two pieces in a line and is similar to a pin. In fact, a skewer is sometimes described as a "reverse pin"; the difference is that in a skewer, the more valuable piece is in front of the piece of lesser or equal value...

).
A check might force some piece to block it and therefore pose an absolute pin
Pin (chess)
In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

on that piece.
A check might deflect the king from protecting some other piece (particularly in an endgame, to capture opponent's pawns).

History