Zwischenzug
Encyclopedia
The zwischenzug is a 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...

 tactic
Chess tactic
In chess, a tactic refers to a sequence of moves which limits the opponent's options and may result in tangible gain. Tactics are usually contrasted with strategy, in which advantages take longer to be realized, and the opponent is less constrained in responding.The fundamental building blocks of...

 in which a player, instead of playing the expected move (commonly a recapture of the capturer of a piece that the opponent has just captured) first interpolates another move, posing an immediate threat that the opponent must answer, then plays the expected move . Ideally, the zwischenzug changes the situation to the player's advantage, such as by gaining material or avoiding what would otherwise be a strong continuation for the opponent.

Such a move is also called an intermezzo , intermediate move , or in-between move . When the intermediate move is a check, it is sometimes called an "in-between check" , "zwischenschach" , or "zwischen-check" .

As with any fairly common chess tactic, it is impossible to pinpoint when the first zwischenzug was played. Three early examples are Lichtenhein-Morphy
Paul Morphy
Paul Charles Morphy was an American chess player. He is considered to have been the greatest chess master of his era and an unofficial World Chess Champion. He was a chess prodigy...

, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 1857; Rosenthal
Samuel Rosenthal
Samuel Rosenthal was a Jewish chess master. Chess historian Edward Winter wrote, "He dedicated his life to chess-playing, touring, writing, teaching and analysing...

-De Vere, Paris 1867; and Tartakower
Savielly Tartakower
Ksawery Tartakower was a leading Polish and French chess Grandmaster. He was also a leading chess journalist of the 1920s and 30s...

-Capablanca, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 1924. The first known use of the term zwischenzug, however, did not occur until 1933, when the prolific American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 chess authors Fred Reinfeld
Fred Reinfeld
Fred Reinfeld was an American chess master and a prolific writer on chess and many other subjects, whose books are still read today.-Biography:...

 and Irving Chernev
Irving Chernev
Irving Chernev was a prolific Russian-American chess author. He was born in Priluki in the Russian Empire and emigrated to the United States in 1920. Chernev was a national master strength player, and was obsessed with chess...

 used it in their book Chess Strategy and Tactics.

History

No one knows when the first zwischenzug was played, but it was evidently long before the term itself existed. One early example was Lichtenhein-Morphy, New York 1857. In the diagram at right, White has just captured Black's knight
Knight (chess)
The knight is a piece in the game of chess, representing a knight . It is normally represented by a horse's head and neck. Each player starts with two knights, which begin on the row closest to the player, one square from the corner...

 on e4 and surely expected the recapture 10...dxe4 11.0-0, when White's king is safe and he has the better 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...

. Morphy, the strongest player of the day, instead played the zwischenzug 10...Qh4! Now White cannot save the bishop, since a move like 11.Bf3?? is met by 11...Qxf2#. Moreover, 11.0-0 would be met by 11...Qxe4 12.Nc3 Qh4, when "Black has the two bishops and a compact position without serious weakness" . Instead, White played 11.Qe2 (forcing Black to weaken his pawns
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...

) dxe4 12.Be3? (after 12.0-0!, Black has only a slight advantage) Bg4! 13.Qc4 Bxe3!! and Morphy went on to win a brilliancy.
Rosenthal-De Vere, Paris 1867, is another 19th-century example of a zwischenzug . De Vere (Black) had earlier sacrificed
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....

 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...

 for two pawns. White has just played 16.Bxb4. Instead of recapturing with 16...Qxb4+, De Vere first played the zwischenzug (or zwischenschach) 16...Rc1+! After 17.Kd2 Rxf1 18.Qxf1 Qxb4+ 19.Ke2 Qxf4 20.Qg1 Nxe5, De Vere's zwischenzug had netted him two more pawns, leaving him with the material advantage of four pawns for a knight. White resigned after twelve more moves.
Another prominent example that brought the concept of zwischenzug, albeit not the term itself, to public attention was Tartakower-Capablanca, New York 1924. This was a game won by the reigning 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....

 at one of the strongest tournament
Tournament
A tournament is a competition involving a relatively large number of competitors, all participating in a sport or game. More specifically, the term may be used in either of two overlapping senses:...

s of the early 20th century. In the position at right, Tartakower (White) has just played 9. Bxb8, thinking he has caught Capablanca in a trap: if 9...Rxb8, 10.Qa4+ and 11.Qxb4 wins 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...

 . However, Capablanca sprang the zwischenzug 9...Nd5!, protecting his bishop and also threatening 10...Ne3+, forking
Fork (chess)
In chess, a fork is a tactic that uses a single piece to attack multiple pieces at the same time. The attacker usually hopes to gain material by capturing one of the opponent's pieces. The defender often finds himself in a difficult position in which he cannot counter all threats. The attacking...

 White's 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...

 and 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 Tartakower's 10.Kf2 Rxb8, Capablanca had regained his piece and went on to win in 20 more moves. Note that after 10.Bf4 (instead of 10.Kf2), Black would not play 10...Nxf4??, which would still allow 11.Qa4+, winning a piece. Instead, after 10.Bf4 Black would play a second zwischenzug, 10...Qf6!, attacking the bishop again, and also renewing the threat of 11...Ne3+ . After a move like 11.Qc1, Black could either take the bishop or consider yet a third zwischenzug with 11...Bd6.
Alekhine, Reinfeld, and Tartakower and du Mont do not call 9...Nd5! a "zwischenzug" in their books (originally published in 1925, 1942, and 1952, respectively). Instead, they refer to it as, respectively, "a bit of finesse", a "sly interpolation", and an "intermediary manoeuvre" .

The earliest known use of the term zwischenzug did not occur until after all of these games. According to chess historian Edward Winter
Edward Winter (chess historian)
Edward Winter is an English journalist, archivist, historian, collector and author about the game of chess. He writes a regular column on that subject, Chess Notes, and is also a regular columnist for ChessBase.-Chess Notes:...

, the first known use was in 1933. Fred Reinfeld and Irving Chernev, annotating the game Max Euwe
Max Euwe
Machgielis Euwe was a Dutch chess Grandmaster, mathematician, and author. He was the fifth player to become World Chess Champion . Euwe also served as President of FIDE, the World Chess Federation, from 1970 to 1978.- Early years :Euwe was born in Watergraafsmeer, near Amsterdam...

-Gyula Breyer
Gyula Breyer
Gyula Breyer was a Hungarian chess player. He was a leading member of the hypermodern school of chess theory, which favored controlling the center with pressure from the flanks....

, Vienna 1921, called Breyer's 27th move, 27...Nge3!, "an important Zwischenzug" . The game can be played over here.

Additional examples

The diagram shows another example. Black, on move, plays
1...Rxh4?

expecting White to play 2. Qxh4, when Black retains a material advantage. However, White has a zwischenzug:
2.Qd8+!

which is followed by
2...Kh7
3.Qxh4+ Kg8
4.Qxg3

and White has won 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...

, leaving him with a winning position.

Mieses-Reshevsky

A zwischenzug occurred in Mieses
Jacques Mieses
----Jacques Mieses was a German-born Jewish chess Grandmaster and writer. He became a naturalized British citizen after World War II.p258-Chess career:...

-Reshevsky, Margate 1935. From the position in the diagram, play continued:
29. Nd4 Bxd4
30. cxd4

White must have expected 30... Qxd4 31. Qxc4 Re1+ and then 32. Kg2 gets him out of trouble, but Black has a zwischenzug:
30... Re4!

Making a double attack on the d-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...

 and preventing the capture of his own pawn. Now if 31. Qxc4, 31... Re1+ forces 32. Rxe1 and White loses his queen .

L. Steiner-Helling

L. Steiner-Helling, Berlin 1928, provides another example of the zwischenschach (in-between check). Black has just captured White's 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...

 on f2 with his knight. White responded with 16.Qxf2, expecting the skewer 16...Bg3??, which he would refute with 17.Qxf7+! Rxf7 18.Re8#. Instead, Black first played the zwischenschach 16...Bh2+! Now 17.Kxh2 Qxf2 loses White's queen. The game continued 17.Kf1 Bg3! Not seeing the point, White blithely continued with his plan: 18. Qxf7+?? Rxf7+ Now White realized that he is in check (that was the point of 16...Bh2+!), so his intended 19.Re8# is illegal. The forced 19.Bxf7+ Kxf7 would leave Black with queen for rook, an easily winning material advantage, so White resigned .

Kerchev-Karastoichev

In the game between Zlatozar Kerchev and Emil Stefanov Karastoichev, Black moved
1... Ng5

discovering an attack on White's queen. White moved:
2. Qxg6

(If White moves the queen to another square, Black's knight captures White's rook on f3, winning the exchange
The exchange (chess)
The exchange in chess refers to a situation in which one player loses a minor piece but captures the opponent's rook. The side which wins the rook is said to have won the exchange, while the other player has lost the exchange, since the rook is usually more valuable...

.) Instead of immediately recapturing the queen, Black played
2... Nxf3+

and White must get out of check. After
3. Bxf3 hxg6

Black had won the exchange .
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