Perpetual check
Encyclopedia
In the game of 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...

, perpetual check is a situation in which one player can force a 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,...

 by an unending series of checks. Such a situation typically arises when the player who is checking cannot deliver 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...

; while failing to continue the series of checks gives the opponent at least a chance to win. A draw by perpetual check is no longer one of the rules of chess
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...

. However, such a situation will eventually result in a draw by either threefold repetition
Threefold repetition
In chess and some other abstract strategy games, the threefold repetition rule states that a player can claim a draw if the same position occurs three times, or will occur after their next move, with the same player to move. The repeated positions need not occur in succession...

 or the fifty-move rule, but usually players agree to a draw
Draw by agreement
In chess, a draw by agreement is the outcome of a game due to the agreement of both players to a draw. A player may offer a draw to his opponent at any stage of a game; if the opponent accepts, the game is a draw. The relevant portion of the FIDE laws of chess is article 9.1...

 .

Perpetual check can also occur in other 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, although the rules relating to it may be different. For example, giving perpetual check is not allowed (an automatic loss for the giver) in both 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...

.

Examples

In this diagram, Black is ahead a 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...

, a 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 a pawn
Pawn (chess)
The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...

 which would normally be a decisive material advantage. But White, to move, can draw by perpetual check:
1. Qe8+ Kh7
2. Qh5+ Kg8
3. Qe8+ etc .

The same position will soon repeat for the third time and White can claim a draw by threefold repetition; or the players will agree to a draw.

Unzicker versus Averbakh

In the second diagram, from Unzicker
Wolfgang Unzicker
Wolfgang Unzicker was one of the strongest German chess Grandmasters from 1945 to about 1970.He decided against making chess his profession, choosing law instead....

 versus Averbakh
Yuri Averbakh
Yuri Lvovich Averbakh is a Soviet and Russian chess player and author. He is currently the oldest living chess grandmaster.-Life and career:...

, Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

 Interzonal
Interzonal
Interzonal chess tournaments were tournaments organized by FIDE, the World Chess Federation, and were a stage in the triennial World Chess Championship cycle.- Zonal tournaments :...

 1952, Black (on move) would soon be forced to give up one of his rooks
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...

 for White's c-pawn
Pawn (chess)
The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...

 (to prevent it from promoting
Promotion (chess)
Promotion is a chess rule describing the transformation of a pawn that reaches its eighth rank into the player's choice of a queen, knight, rook, or bishop of the same color . The new piece replaces the pawn on the same square and is part of the move. Promotion is not limited to pieces that have...

 or to capture the promoted 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...

 after promotion). He can, however, exploit the weakness of White's kingside pawn structure
Pawn structure
In chess, the pawn structure is the configuration of pawns on the chessboard. Since pawns are the least mobile of the chess pieces, the pawn structure is relatively static and thus largely determines the strategic nature of the position.-General observations:Weaknesses in the pawn structure, such...

 with
1... Rxc7!
2. Qxc7 Ng4! (threatening 3...Qh2#)
3. hxg4 Qf2+

salvaging a draw by threefold repetition with checks on h4 and f2.

Hamppe versus Meitner

In the classic game between Carl Hamppe
Carl Hamppe
Carl Hamppe was a senior government official in Vienna as well as a Swiss–Austrian chess master and theoretician....

 and Philipp Meitner
Philipp Meitner
Philipp Meitner was an Austrian lawyer and chess master. His most famous game was the "Immortal Draw" . He won at Vienna 1875, and won a match against Adolf Schwarz at Vienna 1878.Meitner played in two strong international tournaments in the Vienna 1873 and Vienna 1882...

 in Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

 1872, following a series of sacrifices
Sacrifice (chess)
In chess, a sacrifice is a move giving up a piece in the hopes of gaining tactical or positional compensation in other forms. A sacrifice could also be a deliberate exchange of a chess piece of higher value for an opponent's piece of lower value....

 Black forces the game to the position in the diagram, a perpetual check:
16...Bb7+!
17.Kb5 (17.Kxb7?? Kd7 18.Qg4+ Kd6 followed by ...Rhb8#)
17...Ba6+
18.Kc6 (18.Ka4?? Bc4 and 19...b5#)
18...Bb7+ ½-½


Leko versus Kramnik

In the game between Peter Leko
Péter Lékó
On the way to winning the prestigious Corus chess tournament in 2005, Lékó defeated Grandmaster Viswanathan Anand with the black pieces. The moves were:...

 and Vladimir Kramnik
Vladimir Kramnik
Vladimir Borisovich Kramnik is a Russian chess grandmaster. He was the Classical World Chess Champion from 2000 to 2006, and the undisputed World Chess Champion from 2006 to 2007...

 at the 2008 Corus tournament
Corus chess tournament
The Tata Steel Chess Tournament formerly called the Corus chess tournament takes place every year, usually in January, in a small town called Wijk aan Zee, part of the larger Beverwijk in the province of North Holland in the Netherlands...

, Black was able to obtain a draw because of perpetual check:
24... Qb4+
25. Ka2 Qa4+
26. Kb2 Qb4+
27. Kc1 Qa3+
28. Kb1 ½–½


Fischer versus Tal

A perpetual check saved a draw for Mikhail Tal
Mikhail Tal
Mikhail Tal was a Soviet–Latvian chess player, a Grandmaster, and the eighth World Chess Champion.Widely regarded as a creative genius, and the best attacking player of all time, he played a daring, combinatorial style. His play was known above all for improvisation and unpredictability....

 against Bobby Fischer
Bobby Fischer
Robert James "Bobby" Fischer was an American chess Grandmaster and the 11th World Chess Champion. He is widely considered one of the greatest chess players of all time. Fischer was also a best-selling chess author...

 in this 1960 game, played in the 14th Chess Olympiad
14th Chess Olympiad
The 14th Chess Olympiad, organized by the FIDE and comprising an open and women's tournament, as well as several events designed to promote the game of chess, took place between October 26 and November 9, 1960, in Leipzig, East Germany.-References:...

, while Tal was the World Champion
World Chess Championship
The World Chess Championship is played to determine the World Champion in the board game chess. Men and women of any age are eligible to contest this title....

. In this position Black played 21... Qg4+ and the game was drawn . (After 22. Kh1 then 22... Qf3+ 23. Kg1 Qg4+ forces perpetual check.)

History

The Oxford Encyclopedia of Chess Games, Volume 1 (1485-1866) includes all recorded games played up to 1800 . The earliest example of perpetual check contained in it is a game played by two unknown players in 1750: N.N. versus Unknown, 1750 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.0-0 (the rules of castling
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...

 not yet having been standardized in their current form, White moved his king to h1 and his rook to f1) Nf6 5.Nc3 Ng4 6.d3 0-0 (Black moved his king to h8 and his rook to f8) 7.Ng5 d6 8.h3 h6 9.Nxf7+ Rxf7 10.Bxf7 Qh4 11.Qf3 Nxf2+ 12.Rxf2 Bxf2 13.Nd5 Nd4 14.Ne7 Nxf3 15.Ng6+ Kh7 ½-½ in light of 16.Nf8+ Kh8 17.Ng6+ etc. The next examples of perpetual check in the book are two games, both ending in perpetual check, played in 1788 between Bowdler and Philidor
François-André Danican Philidor
François-André Danican Philidor , often referred to as André Danican Philidor during his lifetime, was a French composer and chess player. He contributed to the early development of the opéra comique...

, with Philidor giving odds
Chess handicap
A handicap in chess is a way to enable a weaker player to have a chance of winning against a stronger one. There are many kinds of such handicaps, such as material odds, extra moves A handicap (or "odds") in chess is a way to enable a weaker player to have a chance of winning against a stronger...

 of pawn and move .

A draw by perpetual check used to be in the rules of chess
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...

 , . Howard Staunton
Howard Staunton
Howard Staunton was an English chess master who is generally regarded as having been the world's strongest player from 1843 to 1851, largely as a result of his 1843 victory over Saint-Amant. He promoted a chess set of clearly distinguishable pieces of standardised shape—the Staunton pattern—that...

 gave it as one of six ways to draw a game in The Chess-Player's Handbook . It has since been removed because perpetual check will eventually allow a draw claim by either threefold repetition
Threefold repetition
In chess and some other abstract strategy games, the threefold repetition rule states that a player can claim a draw if the same position occurs three times, or will occur after their next move, with the same player to move. The repeated positions need not occur in succession...

 or the fifty-move rule. If a player demonstrates intent to perform perpetual check, the players usually agree to a draw
Draw by agreement
In chess, a draw by agreement is the outcome of a game due to the agreement of both players to a draw. A player may offer a draw to his opponent at any stage of a game; if the opponent accepts, the game is a draw. The relevant portion of the FIDE laws of chess is article 9.1...

.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK