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Checkmate (often shortened to mate) is a game position in chess (and in other board games of the chaturanga family) in which a player's king is threatened with capture (i.e. is in check) and there is no legal move to escape the threat.
Delivering checkmate is the ultimate goal in chess: a player who is checkmated loses the game. In chess the king is never actually captured – the game ends as soon as the king is checkmated.[note 1] In master and serious amateur play, most players resign an inevitably lost game before being checkmated, and it is considered bad etiquette to continue playing in a completely hopeless position (Burgess 2009:526).[note 2]
If a player's king is in check but the threat can be met, then it is not in checkmate. If a player is not in check but has no legal move, then it is stalemate, and the game immediately ends in a draw. (See rules of chess.)
|This article uses algebraic notation to describe chess moves.|
A checkmate may occur in as few as two moves with all of the pieces still on the board (as in Fool's mate, in the opening phase of the game), in a middlegame position (as in the 1956 game called the Game of the Century between Donald Byrne and Bobby Fischer), or after many moves with as few as three pieces in an endgame position.
In early Sanskrit chess (c. 500–700) the king could be captured and this ended the game. The Persians (c. 700–800) introduced the idea of warning that the king was under attack (announcing check in modern terminology). This was done to avoid the early and accidental end of a game. Later the Persians added the additional rule that a king could not be moved into check or left in check. As a result, the king could not be captured (Davidson 1949:22). Checkmate was thus the logical and only decisive way of ending a game (since if it was checkmate, any move would be illegal) (Davidson 1949:63–64).
Before about 1600 the game could also be won by capturing all of the opponent's pieces other than the king (annihilation or robado) (see bare king). In Medieval times players began to consider it nobler to win by checkmate, so annihilation became a half-win for a while, until it was abandoned (Davidson 1949:63–64).
The term checkmate is an alteration of the Persian phrase "shāh māt" (شاه مات) which means, literally, "the King is helpless" (or "ambushed", "defeated", or "stumped", but not "dead"). It is a common misconception that it means "the King is dead", as chess reached Europe via the Islamic world, and Arabic māta (مَاتَ) means "died" or "is dead" (Hooper & Whyld 1992), (Davidson 1949:70), (Sunnucks 1970), (McKean 2005), (Golombek 1976:27), (Murray 2012:159). However, in the Pashto language (an Iranian language), the word māt (مات) still exists meaning "destroyed, broken".
Moghadam traced the etymology of the word mate. It comes from a Persian verb mandan (ماندن), meaning "to remain", which is cognate with the Latin word maneō and the Greek menō (μενω, which means "I remain"). It means "remained" in the sense of "abandoned" and the formal translation is "surprised", in the military sense of "ambushed" (not in the sense of "astonished") (Davidson 1949:70–71). "Shāh" (شاه) is the New Persian word for the monarch. Players would announce "Shāh" when the king was under attack (in check). "Māt" (مات) is a Persian adjective for "at a loss", "helpless", or "defeated". So the king is in mate when he is ambushed, at a loss, helpless, defeated, or abandoned to his fate (Murray 2012:159).
Two major pieces (queens or rooks) can easily force checkmate on the edge of the board, even without the help of their king. The process is to put the two pieces on adjacent ranks or files and gradually force the king to the side of the board, where one piece keeps the king on the edge of the board while the other delivers checkmate (Pandolfini 1988:18–20).
In the first diagram, White checkmates easily by forcing the black king to the edge a rank at a time or a file at a time:
The checkmate with two queens or with two rooks is similar (Pandolfini 1988:18–20).
Here are the common fundamental checkmates when one side has only his king and the other side has only the minimum material needed to force checkmate, i.e. (1) one queen, (2) one rook, (3) two bishops on opposite-colored squares, or (4) a bishop and a knight. The king must help in accomplishing all of these checkmates. If the superior side has more material, checkmates are easier (Silman 2007:33).
The checkmate with the queen is the most important, but it is also very easy to achieve. It often occurs after a pawn has queened. The next most important one is the checkmate with the rook, and it is also very easy to achieve. The checkmates with the two bishops and with a bishop and knight are not nearly as important, since they only occur infrequently. The two bishop checkmate is fairly easy to accomplish, but the bishop and knight checkmate is difficult and requires precision.
The first two diagrams show representatives of the basic checkmate positions with a queen, which can occur on any edge of the board. Naturally, the exact position can vary from the diagram. In the first of the checkmate positions, the queen is directly in front of the opposing king and the white king is protecting its queen. In the second checkmate position, the kings are in opposition and the queen mates on the rank (or file) of the king. See Wikibooks – Chess/The Endgame for a demonstration of how the king and queen versus king mate is achieved.
With the side with the queen to move, checkmate can be forced in at most ten moves from any starting position, with optimal play by both sides, but usually fewer moves are required (Fine & Benko 2003:1–2). (Müller & Lamprecht 2001:16). In positions in which a pawn has just promoted to a queen, at most nine moves are required (Levy & Newborn 1991:144).
In the position at left, White checkmates by confining the black king to a rectangle and shrinking the rectangle to force the king to the edge of the board:
The superior side must be careful to not stalemate the opposing king, whereas the defender would like to get into such a position. There are two general types of stalemate positions that can occur, which the winning side must avoid (Fine & Benko 2003:2).
The first diagram shows the basic checkmate position with a rook, which can occur on any edge of the board. The black king can be on any square on the edge of the board, the white king is in opposition to it, and the rook can check from any square on the rank or file (assuming that it can not be captured). The second diagram shows a slightly different position where the kings are not in opposition but the defending king must be in a corner.
With the side with the rook to move, checkmate can be forced in at most sixteen moves from any starting position (Fine & Benko 2003:2). Again, see Wikibooks – Chess/The Endgame for a demonstration of how the king and rook versus king mate is achieved.
In the third diagram position, White checkmates by confining the black king to a rectangle and shrinking the rectangle to force the king to the edge of the board:
There are two stalemate positions to watch out for (Fine & Benko 2003:2–3):
Here are the two basic checkmate positions with two bishops (on opposite-colored squares), which can occur in any corner. (Two or more bishops on the same color, which could occur because of pawn promotion, cannot checkmate.) The first is a checkmate in the corner. The second position is a checkmate in a side square next to the corner square. With the side with the bishops to move, checkmate can be forced in at most nineteen moves (Müller & Lamprecht 2001:17). If the side with the bishops is to move, they can force checkmate except in some very rare positions (Speelman, Tisdall & Wade 1993:7).
It is not too difficult for two bishops to force checkmate, with the aid of their king. Two principles apply:
In the position from Seirawan, White wins by first forcing the black king to the side of the board, then to a corner, and then checkmates. It can be any side of the board and any corner. The process is:
Note that this is not the shortest forced checkmate from this position. Müller and Lamprecht give a fifteen-move solution, however it contains an inaccurate move by Black (according to endgame tablebases) (Müller & Lamprecht 2001:17). With optimal play by both sides, checkmate in this position requires seventeen moves. An optimal variation is:
Of the basic checkmates, this is the most difficult one to force, because these two pieces cannot form a linear barrier to the enemy king from a distance. Also, the checkmate can be forced only in a corner that the bishop controls. (Müller & Lamprecht 2001:18) If the side with the bishop and knight is to move, they can force checkmate except in some rare positions (Speelman, Tisdall & Wade 1993:7).
Two basic checkmate positions are shown with a bishop and a knight, or the bishop and knight checkmate. The first position is a checkmate by the bishop, with the king in the corner. The second position is a checkmate by the knight, with the king in a side square next to the corner. Alternatively, the knight can be on c6 or d7 in the second position.
With the side with the bishop and knight to move, checkmate can be forced in at most thirty-three moves from any starting position (Müller & Lamprecht 2001:19), except those in which the defending king is initially forking the bishop and knight and it is not possible to defend both. However, the mating process requires accurate play, since a few errors could result in a draw either by the fifty-move rule or stalemate.
Opinions differ as to whether or not a player should learn this checkmate procedure. James Howell omits the checkmate with two bishops in his book because it rarely occurs but includes the bishop and knight checkmate. Howell says that he has had it three times (always on the defending side) and that it occurs more often than the checkmate with two bishops (Howell 1997:138). On the other hand, Jeremy Silman includes the checkmate with two bishops but not the bishop plus knight checkmate because he has had it only once and his friend John Watson has never had it (Silman 2007:33,188). Silman says:
... mastering it would take a significant chunk of time. Should the chess hopeful really spend many of his precious hours he's put aside for chess study learning an endgame he will achieve (at most) only once or twice in his lifetime?
It is impossible to force checkmate with a king and two knights, although checkmate positions are possible (see the first diagram). In the second diagram, if Black plays 1... Ka8? White can checkmate with 2. Nbc7#, but Black can play 1... Kc8 and escape the threat. The defender's task is easy — he simply has to avoid moving into a position in which he can be checkmated on the next move, and he always has another move available in such situations (Speelman, Tisdall & Wade 1993:11).
In the third diagram, White can play 1. Nc6+ Ka8, but now if White plays 2. Nb5 or 2. Ne8 threatening 3. Nc7#, Black is stalemated. It is sometimes possible to force checkmate with two knights against a pawn, because in some positions, having a pawn removes this stalemate defence.
Under some circumstances, two knights and a king can force checkmate against a king and pawn (or rarely more pawns). The winning plan, quite difficult to execute in practice, is to blockade the enemy pawn(s) with one of the knights, maneuver the enemy king into a stalemated position, then bring the other knight over to checkmate. (See two knights endgame.)
Three knights and a king can force checkmate against a lone king within twenty moves (assuming that the lone king cannot quickly win a knight) (Fine 1941:5–6). These situations are generally only seen in chess problems, since at least one of the knights must be a promoted piece, and there is very rarely a reason (e.g., avoidance of stalemate) to promote a pawn to anything other than a queen (see underpromotion).
A back-rank checkmate is a checkmate delivered by a rook or queen along a back rank (that is, the row on which the pieces [not pawns] stand at the start of the game) in which the mated king is unable to move up the board because the king is blocked by friendly pieces (usually pawns) on the second rank (Burgess 2009:16). An example of a back-rank checkmate is shown in one of the diagrams. It is also known as the corridor mate.
Scholar's Mate (also known as the four-move checkmate) is the checkmate achieved by the moves:
The moves might be played in a different order or in slight variation, but the basic idea is the same: the queen and bishop combine in a simple mating attack on f7 (or f2 if Black is performing the mate). There are also other ways to checkmate in four moves.
Fool's Mate, also known as the "Two-Move Checkmate", is the quickest possible checkmate. A prime example consists of the moves:
The mate is usually seen in a corner of the board, since fewer pieces are needed to surround the king there. The most common form of smothered mate is seen in the diagram to the right. The knight on f7 delivers mate to the king on h8 which is prevented from escaping the check by the rook on g8 and the pawns on g7 and h7. Similarly, White can be mated with the white king on h1 and the knight on f2. Analogous mates on a1 and a8 are rarer, because kingside castling is the more common as it safely places the king closer to the corner than it would had the castling occurred on the queenside.
Boden's Mate is a checkmate characterized by bishops on two criss-crossing diagonals (for example, bishops on a6 and f4 delivering mate to a king on c8), with possible flight squares for the king being occupied by friendly pieces. Most often the checkmated king has castled queenside, and is mated on c8 or c1. Many variants on the mate are seen, for example a king on e8 checkmated by bishops on g6 and a3, and a king on f1 checkmated by bishops on h3 and b6. Often the mate is immediately preceded by a sacrifice that opens up the diagonal on which the bishop delivers checkmate.
In some rare positions it is possible to force checkmate with a king and bishop versus a king and pawn or a king and knight versus a king and pawn.
White also wins if Black is to move first:
There are also positions in which a king and a knight can checkmate a king and a bishop, knight, or rook; or a king and a bishop can checkmate a king with a bishop on the other color of squares or with a knight, but the checkmate cannot be forced if there is no other material on the board (see the diagrams for some examples). Nevertheless, it keeps these material combinations from being ruled a draw because of "insufficient mating material" or "impossibility of checkmate" under the FIDE rules of chess.[note 3]