Two Knights Endgame
The two knights endgame is a chess endgame with a king and two knights versus a king. In contrast to a king and two bishops (on opposite-colored squares), or a bishop and a knight, a king and two knights cannot checkmate against a lone king (however, the superior side can force stalemate). Although there are checkmate positions, a king and two knights cannot them against proper, relatively easy defense. Paradoxically, although the king and two knights cannot checkmate of the lone king, there are positions in which the king and two knights can force checkmate against a king and some additional material. The extra material of the defending side provides moves that prevent the defending king from being stalemated. The winning chances with two knights are insignificant except against a few pawns. These positions were studied extensively by A. A. Troitsky, who discovered the Troitsky line, a line on or behind which the defending side's pawn must be securely blockaded for the attac ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Chess Kll45
Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to distinguish it from related games, such as xiangqi (Chinese chess) and shogi (Japanese chess). The recorded history of chess goes back at least to the emergence of a similar game, chaturanga, in seventh-century India. The rules of chess as we know them today emerged in Europe at the end of the 15th century, with standardization and universal acceptance by the end of the 19th century. Today, chess is one of the world's most popular games, played by millions of people worldwide. Chess is an abstract strategy game that involves no hidden information and no use of dice or cards. It is played on a chessboard with 64 squares arranged in an eight-by-eight grid. At the start, each player controls sixteen pieces: one king, one queen, two rooks, two bi ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Fork (chess)
In chess, a fork is a tactic in which a piece multiple enemy pieces simultaneously. The attacker usually aims to capture one of the forked pieces. The defender often cannot counter every threat. A fork is most effective when it is forcing, such as when the king is put in check. A fork is a type of . Terminology A fork is an example of a . The type of fork is named after the type of forking piece. For example, a fork by a knight is a knight fork. The attacked pieces are ''forked''. If the King is one of the attacked pieces, the term ''absolute fork'' is sometimes used. A fork not involving the enemy king is in contrast a ''relative fork''. A fork of the king and queen, the highest material-gaining fork possible, is sometimes called a ''royal fork''. A fork of the enemy king, queen, and one (or both) rooks is sometimes called a ''grand fork''. A knight fork of the enemy king, queen, and possibly other pieces is sometimes called a ''family fork'' or ''family check''. Strategy ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Endgame Tablebase
An endgame tablebase is a computerized database that contains precalculated exhaustive analysis of chess endgame positions. It is typically used by a computer chess engine during play, or by a human or computer that is retrospectively analysing a game that has already been played. The tablebase contains the game-theoretical value (win, loss, or draw) in each possible position, and how many moves it would take to achieve that result with perfect play. Thus, the tablebase acts as an oracle, always providing the optimal moves. Typically the database records each possible position with certain pieces remaining on the board, and the best moves with White to move and with Black to move. Tablebases are generated by retrograde analysis, working backward from a checkmated position. By 2005, all chess positions with up to six pieces, including the two kings, had been solved. By August 2012, tablebases had solved chess for almost every position with up to seven pieces, but the positio ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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John Nunn
John Denis Martin Nunn (born 25 April 1955) is an English chess grandmaster, a three-time world champion in chess problem solving, a chess writer and publisher, and a mathematician. He is one of England's strongest chess players and was formerly in the world's top ten. Education and early life Nunn was born in London. As a junior, he showed a prodigious talent for the game and in 1967, at twelve years of age, he won the British under-14 Championship. At fourteen, he was London Under-18 Champion for the 1969–70 season and less than a year later, at just fifteen years of age, he proceeded to Oriel College, Oxford, to study mathematics. At the time, Nunn was Oxford's youngest undergraduate since Cardinal Wolsey in 1520. Graduating in 1973, he went on to gain his Doctor of Philosophy degree in 1978 with a thesis on finite H-spaces supervised by John Hubbuck. Nunn remained in Oxford as a mathematics lecturer until 1981, when he became a professional chess player. Career In 19 ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Fifty-move Rule
The fifty-move rule in chess states that a player can claim a draw if no has been made and no pawn has been moved in the last fifty moves (for this purpose a "move" consists of a player completing a turn followed by the opponent completing a turn). The purpose of this rule is to prevent a player with no chance of winning from obstinately continuing to play indefinitely or seeking to win by tiring the opponent. Chess positions with only a few pieces can be " solved", that is, the outcome of best play for both sides can be determined by exhaustive analysis; and if the outcome is a win for one side or the other (rather than a draw), it is of interest to know whether the defending side can hold out long enough to invoke the fifty-move rule. The simplest common endings, called the basic checkmates, such as king and queen versus king, can all be won in well under 50 moves. However, in the 20th century it was discovered that certain endgame positions are winnable but require more than 5 ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Pawn (chess)
The pawn (♙, ♟) is the most numerous and weakest piece in the game of chess. It may move one vacant square directly forward, it may move two vacant squares directly forward on its first move, and it may capture one square diagonally forward. Each player begins a game with eight pawns, one on each square of their second . The white pawns start on a2 through h2; the black pawns start on a7 through h7. Individual pawns are referred to by the on which they stand. For example, one speaks of "White's f-pawn" or "Black's b-pawn". Alternatively, they can be referred to by the piece which stood on that file at the beginning of the game, e.g. "White's king bishop's pawn" or "Black's queen knight's pawn". It is also common to refer to a rook's pawn, meaning any pawn on the a- or h-files, a knight's pawn (on the b- or g-files), a bishop's pawn (on the c- or f-files), a queen's pawn (on the d-file), a king's pawn (on the e-file), and a central pawn (on the d- or e-files). The pawn histori ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tempo (chess)
In chess and other chess-like games, a tempo is a "turn" or single move (a half-move or ply made either by White or Black). When a player achieves a desired result in one fewer move, the player is said to "gain a tempo"; conversely, when a player takes one more move than necessary, the player is said to "lose a tempo". Similarly, when a player forces their opponent to make moves not according to their initial plan, one is said to "gain tempo" because the opponent is wasting moves. A move that gains a tempo is often called "a move with tempo". A simple example of losing a tempo may be moving a rook from the h1-square to h5 and from there to h8 in the first diagram; simply moving from h1 to h8 would have achieved the same result with a tempo to spare. However, such maneuvers do not always lose a tempo—the rook on h5 may make some threat which needs to be responded to. In this case, since both players have "lost" a tempo, the net result in terms of time is nil, but the change broug ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Chess Pdl45
Chess is a board game for two players, called White and Black in chess, White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's King (chess), king. It is sometimes called international chess or Western chess to distinguish it from chess variant, related games, such as xiangqi (Chinese chess) and shogi (Japanese chess). The recorded history of chess goes back at least to the emergence of a similar game, chaturanga, in seventh-century History of India, India. The rules of chess as we know them today emerged in Europe at the end of the 15th century, with standardization and universal acceptance by the end of the 19th century. Today, chess is one of the world's most popular games, played by millions of people worldwide. Chess is an abstract strategy game that involves Perfect information, no hidden information and no use of dice or cards. It is played on a chessboard with 64 squares arranged in an eight-by-eight grid. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Retrograde Analysis
In chess problems, retrograde analysis is a technique employed to determine which moves were played leading up to a given position. While this technique is rarely needed for solving ordinary chess problems, there is a whole subgenre of chess problems in which it is an important part; such problems are known as ''retros''. Retros may ask, for example, for a mate in two, but the main puzzle is in explaining the history of the position. This may be important to determine, for example, if castling is disallowed or an ''en passant'' capture is possible. Other problems may ask specific questions relating to the history of the position, such as, "Is the bishop on c1 promoted?". This is essentially a matter of logical reasoning, with high appeal for puzzle enthusiasts. Sometimes it is necessary to determine if a particular position is legal, with "legal" meaning that it could be reached by a series of legal moves, no matter how illogical. Another important branch of retrograde analysi ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Viktor Korchnoi
Viktor Lvovich Korchnoi ( rus, Ви́ктор Льво́вич Корчно́й, p=vʲiktər lʲvovʲɪtɕ kɐrtɕˈnoj; 23 March 1931 – 6 June 2016) was a Soviet (before 1976) and Swiss (after 1980) chess grandmaster (GM) and chess writer. He is considered one of the strongest players never to have become World Chess Champion. Born in Leningrad, Soviet Union (USSR), Korchnoi defected to the Netherlands in 1976, and resided in Switzerland from 1978, becoming a Swiss citizen. Korchnoi played four matches, three of which were official, against GM Anatoly Karpov. In 1974, Korchnoi lost the Candidates Tournament final to Karpov. Karpov was declared World Champion in 1975 when GM Bobby Fischer declined to defend his title. Korchnoi then won two consecutive Candidates cycles to qualify for World Chess Championship matches with Karpov in 1978 and 1981 but lost both. The two players also played a drawn training match of six games in 1971. Korchnoi was a candidate for the World Champio ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Anatoly Karpov
Anatoly Yevgenyevich Karpov ( rus, links=no, Анато́лий Евге́ньевич Ка́рпов, p=ɐnɐˈtolʲɪj jɪvˈɡʲenʲjɪvʲɪtɕ ˈkarpəf; born May 23, 1951) is a Russian and former Soviet chess grandmaster, former World Chess Champion, and politician. He was the 12th World Chess Champion from 1975 to 1985, a three-time FIDE World Champion (1993, 1996, 1998), twice World Chess champion as a member of the USSR team (1985, 1989), and a six-time winner of Chess Olympiads as a member of the USSR team (1972, 1974, 1980, 1982, 1986, 1988). The International Association of Chess Press awarded him nine Chess Oscars (1973, 1974, 1975, 1976, 1977, 1979, 1980, 1981, 1984). Karpov's chess tournament successes include over 160 first-place finishes. He had a peak Elo rating of 2780, and his 102 total months at world number one is the third-longest of all time, behind Magnus Carlsen and Garry Kasparov, since the inception of the FIDE ranking list in 1970. Karpov is a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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World Chess Championship 1981
The 1981 World Chess Championship was played between Anatoly Karpov and Viktor Korchnoi in Merano, Italy from October 1 to November 19, 1981. Karpov won with six wins against two, with 10 draws. The two players had already played against each other in the World Chess Championship match 1978 in the Philippines, when Karpov also won. 1979 Interzonal tournaments Two Interzonals were held in 1979, one in Riga and the other in Rio de Janeiro. : The Riga interzonal was won in dominant fashion by Tal, who went through the tournament undefeated ahead of Polugaevsky. They were joined in the Candidates Tournament by Adorján, whose better tie-break score in the main tournament put him ahead of Ribli, after the two drew a playoff in Budapest 3-3. The game between Gruenfeld and Bouaziz was not played, as part of the Arab boycott of Israeli sportspeople. Bouaziz forfeited and Gruenfeld received a point. : The Interzonal in Rio saw Portisch, Petrosian and Hübner share first pl ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |