Sacrifice (chess) - AbsoluteAstronomy.com

In 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...

, a sacrifice is a move giving up a piece

Chess piece

Chess pieces or chessmen are the pieces deployed on a chessboard to play the game of chess. The pieces vary in abilities, giving them different values in the game...

in the hopes of gaining tactical or positional compensation in other forms. A sacrifice could also be a deliberate exchange

Exchange (chess)

In the tactics and strategy in the board game of chess, an exchange or trade of chess pieces is series of closely related moves, typically sequential, in which the two players capture each others pieces. Any types of pieces except the kings may possibly be exchanged, i. e. captured in an...

of a chess piece of higher value for an opponent's piece of lower value.

Any chess piece

Chess piece

Chess pieces or chessmen are the pieces deployed on a chessboard to play the game of chess. The pieces vary in abilities, giving them different values in the game...

except 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...

can be sacrificed. Because players usually try to hold onto their own pieces, offering a sacrifice can come as an unpleasant surprise to one's opponent, putting him off balance, and causing him to waste much precious time trying to calculate whether the sacrifice is sound or not and whether to accept it. Sacrificing one'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...

(the most valuable piece), or a string of pieces, adds to the surprise, and such games can be awarded brilliancy prizes.

Real versus sham

Rudolf Spielmann

Rudolf Spielmann was an Austrian-Jewish chess player of the romantic school, and chess writer.-Career:He was a lawyer but never worked as one....

proposed a division between sham and real sacrifices:

In a real sacrifice, the sacrificing player will often have to play on with less material than his opponent for quite some time.
In a sham sacrifice, the player offering the sacrifice will soon regain material of the same or greater value, or else force mate. A sham sacrifice of this latter type is sometimes known as a pseudo sacrifice.

In compensation for a real sacrifice, the player receives dynamic advantages which he must capitalize on, or risk losing the game due to the material deficit. Because of the risk involved, real sacrifices are also called speculative sacrifices.

Real sacrifices

Attack on the king. A player might sacrifice a pawn or piece to get open lines around the vicinity of the opponent's king, to get a kingside space advantage, to destroy or damage the opposing king's pawn cover, or to keep the opposing king in the center. Unless the opponent manages to fend off the attack, he is likely to lose. The Greek gift sacrifice

Greek gift sacrifice

In chess, the Greek gift sacrifice or classical bishop sacrifice is a typical sacrifice of a bishop by White playing Bxh7+ or Black playing Bxh2+....

is a canonical example.

Development. It is common to give up a pawn in the opening to speed up one's development. Gambit

Gambit

A gambit is a chess opening in which a player, most often White, sacrifices material, usually a pawn, with the hope of achieving a resulting advantageous position. Some well-known examples are the King's Gambit , Queen's Gambit , and Evans Gambit...

s typically fall into this category. Developing sacrifices are frequently returned at some point by the opponent before the development edge can turn into a more substantial threat such as a kingside attack.

Strategic/positional. In a general sense, the aim of all real sacrifices is to obtain a positional advantage. However, there are some speculative sacrifices where the compensation is in the form of an open file or diagonal or a weakness in the opponent's 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...

. These are the hardest sacrifices to make, requiring deep strategic understanding.

Sham sacrifices

Checkmate. A common benefit of making a sacrifice is to allow the sacrificing player to 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...

the opponent. Since checkmate is the ultimate goal of chess, the loss of material (see Chess piece relative value) does not matter in a successful checkmate. Sacrifices leading to checkmate are typically forcing, and often checks, leaving the opponent with only one or a few options (example, checking the king with the knight, queen takes the knight, then rook checkmates the king with absence on the queen).

Avoiding loss. The counterpart to the above is saving a lost game. A sacrifice could be made to force stalemate

Stalemate

Stalemate is a situation in chess where the player whose turn it is to move is not in check but has no legal moves. A stalemate ends the game in a draw. Stalemate is covered in the rules of chess....

or 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...

, to create a fortress

Fortress (chess)

In chess, the fortress is an endgame drawing technique in which the side behind in material sets up a zone of protection around their king that cannot be penetrated by the opponent. This only works when the opponent does not have a passed pawn or cannot create one, unless that pawn can be stopped...

, or otherwise 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,...

, or to avoid even greater loss of material.

Material gain. A sacrifice might initiate a combination that results in an overall material gain, making the upfront investment of the sacrifice worthwhile. A sacrifice leading to a pawn promotion

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...

is a special case of this type of sacrifice.

Simplification. Even if the sacrifice leads to net material loss for the foreseeable future, the sacrificing player may benefit because they are already ahead in material and the exchanges simplify the position making it easier to win. A player ahead in material may decide that it is worthwhile to get rid of one of the last effective pieces the opponent has.

The tactical sham sacrifices can be categorized further by the mechanism in why the sacrifice is made. Some sacrifices may fall into more than one category.

In deflection sacrifices the aim is to distract one of the opponent's pieces from a square where it is performing a particular duty.
In destruction sacrifices a piece is sacrificed in order to knock away a materially inferior, but tactically more crucial piece, so that the sacrificing player can gain control over the squares the taken chessman controlled.
A magnet sacrifice is similar to a deflection sacrifice, but the motivation behind a magnet sacrifice is to pull an opponent's piece to a tactically poor square, rather than pulling it away from a crucial square.
In a clearance sacrifice the sacrificing player aims to vacate the square the sacrificed piece stood on, either to open up for his own pieces, or to put another, more useful piece on the same square.
In 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"...

sacrifice, the sacrificing player abstains from spending time to prevent the opponent from winning material because the time saved can be used for something even more beneficial, for example pursuing an attack on the king or guiding a passed pawn towards promotion.
In a suicide sacrifice, the sacrificing player aims to rid himself of the remaining pieces capable of performing legal moves, and thereby obtain a stalemate and a draw from a poor position.

Forced vs. non-forced

Another way to classify sacrifices is to distinguish between forcing and non-forcing sacrifices. The former type leave the opponent with no option but acceptance, typically because not doing so would leave them behind in material with no compensation. Non-forcing sacrifices, on the other hand, give the opponent a choice. A common error is to not recognize when a particular sacrifice can be safely declined with no ill-effects.

Deflection sacrifice

In the diagram, GM Aronian's queen on d3 is at the top of the ladder, and his rook on d1 represents the bottom. He mistakenly played 24. exd4??, opening up the e-file for Black's rook. After Svidler played 24... Re1+!, Aronian was forced to resign, because Black's move forces the reply 25. Rxe1 (or 25. Qf1 Qxf1#), after which White's queen is undefended and therefore lost.

This particular type of sacrifice has also been called the "Hook and Ladder trick", for the white queen is precariously at the top of the "ladder", while the rook is at the bottom, supporting it.

Sacrifice to avoid losing

Black played 1... Qxg3? and White drew with 2. Qg8+! Kxg8 (on any other move Black will get mated) 3. Rxg7+!. White intends to keep checking on the seventh rank, and if Black ever captures the rook it is stalemate.

This save from Evans has been dubbed "The Swindle

Swindle (chess)

In chess, a swindle is a ruse by which a player in a losing position tricks his opponent, and thereby achieves a win or draw instead of the expected loss. It may also refer more generally to obtaining a win or draw from a clearly losing position. I. A. Horowitz and Fred Reinfeld distinguish among...

of the Century". White's rook is known as a desperado.

Non-forcing sacrifice

This time Reshevsky is at the receiving end of a sacrifice. White has just played h2–h4. If Black takes the knight he has to give up his own knight on f6 to avoid mate on h7. Instead, he simply ignored the bait and continued developing.

Positional sacrifice

In this game Black played 14... d4! 15. Nxd4 Nd5. In exchange for the sacrificed pawn, Black has obtained a semi-open file

Half-open file

In chess, a half-open file, or semi-open file, is a file with only pawns of one color. The half-open file can provide a line of attack for a player's rook or queen. A half-open file can only be used by the player with no pawns on it....

, a diagonal, an outpost

Outpost (chess)

An outpost is a square which is protected by a pawn and which cannot be attacked by an opponent's pawn. In the figure to the right, c4 is an outpost, occupied by White's knight...

on d5 and saddled White with a backward pawn

Backward pawn

In chess, a backward pawn is a pawn that is behind the pawns of the same color on the adjacent files and that cannot be advanced without loss of material, usually the backward pawn itself....

on d3. The game was eventually drawn.

Sacrifice to checkmate

Example: In the diagram at left with White to move, what sacrifice move should White make?

Answer: Force a bishop sacrifice by moving the white bishop on f5 to g6 with check. The only way for Black to get out of check is to take the checking bishop with Black's pawn on h7. White's queen retakes the pawn now on g6 producing checkmate.

White can force mate in two moves in the diagram at left as follows: 1. Bg6+ hxg6 2. Qxg6#