|Checkmate (frequently shortened to mate) is a situation in chess (and in other boardgames of the chaturanga family) in which one player cannot avoid their king being captured on the next move—it is a check from which there is no escape. A player who is checkmated loses the game. Delivering checkmate is the ultimate goal in chess (although not all games end in checkmate—often a player resigns before checkmate is administered, or the game may end in a draw in several ways).|
It should be noted that the actual capture of the king is not played—the game ends as soon as a position arises in which the capture is unavoidable.
The fastest a player can cause a checkmate is two moves. This occurs in fool´s mate when a player moves their kings bishop´s pawn one or two squares and kings knight´s pawn two squares, and their opponent moves their queen to the file of the opponent´s king´s rook (1. f3 e5 2. g4 Qh4# in algebraic notation).
If a player´s king is threatened with capture, but that threat can be met, then the king is said to be in check (a check may be met by moving the king to a safe square, by interposing a piece between the king and the threatening piece (assuming the attacking piece is not directly next to the king and is also not a knight), or by capturing the threatening piece). If a player is not in check but has no legal move (that is, no move which does not allow their king to be captured), the result of the game is stalemate.
The term is an alteration or Hobson-Jobson of the Persian phrase "Shah Mat" which means, literally, "the King is dead."
Some common or notable mating patterns have names of their own. Apart from the aforementioned fool´s mate, these include scholar´s mate, smothered mate and the back rank mate.
Traditionally, when checkmate occurs (or is thought to be inevitable) one lays one´s king down on its side to indicate that the game has ended (by resigning the game).
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.
The checkmate with the queen is the most important, but it is also very easy to achieve. If 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 occur pretty infrequently. The bishop and knight checkmate occurs more frequently than the two bishop checkmate. The two bishop checkmate is fairly easy to accomplish, but the bishop and knight checkmate is difficult and requires precision. Note that two knights can´t force checkmate against a lone king.
These diagrams show 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. With white to move, checkmate can be forced in at most ten moves from any starting position. In the first position, the queen is directly in front of the opposing king.
In the second position, the kings are in opposition and the queen mates on the rank of the king.
Next is the basic checkmate position with a rook, which can occur on any edge of the board. With white to move, checkmate can be forced in at most 16 moves from any starting position.
Here are the two basic checkmate positions with two bishops (on opposite colors), which can occur in any corner. With white to move, checkmate can be forced in at most 19 moves. The first is a checkmate in the corner:
The second one is a checkmate in a side square next to the corner square:
Bishop and knight
Here are the two basic checkmate positions with a bishop and a knight, which can only be forced in a corner which the bishop controls. With white to move, checkmate can be forced in at most 33 moves from any starting position, except those in which the black king is initially forking the bishop and knight and it is not possible to defend both. However, the mating process is somewhat difficult and requires accurate play, since a few errors could result in a draw either by the fifty move rule or stalemate. 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 d7 in the second position.