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.
[9] As with any fairly common chess tactic, it is impossible to pinpoint when the first zwischenzug was played.
[13] Instead, White correctly played 11.Qe2 (forcing Black to weaken his pawns), but then erred with 11...dxe4 12.Be3?
Another prominent example that brought the concept of zwischenzug, albeit not the term itself, to public attention was Tartakower–Capablanca, New York 1924.
[19] This was a game won by the reigning World Champion at one of the strongest tournaments of the early 20th century.
[20] In the position in the diagram, 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.
[21] However, Capablanca sprang the zwischenzug 9...Nd5!, protecting his bishop and also threatening 10...Ne3+, forking White's king and queen.
[30] From the position in the diagram, play continued: White must have expected 30...Qxd4 31.Qxc4 Re1+ and then 32.Kg2 gets him out of trouble, but Black has a zwischenzug: Making a double attack on the d-pawn and preventing the capture of his own pawn.
The forced 19.Bxf7+ Kxf7 would leave Black with queen for rook, an easily winning material advantage, so White resigned.
[33][34] In the game Zlatozar Kerchev–Emil Stefanov Karastoichev, 1965 (diagram), Black moved discovering an attack on White's queen.
[35] In game 5 of the 2013 World Chess Championship match, Carlsen had captured a bishop with 20.cxb6, and Anand maintained material balance by capturing a knight with 20...fxe4, also attacking White's bishop (see diagram).
Instead of immediately taking the pawn with 21.Bxe4, which would have given Anand the opportunity to fix his queenside pawn weaknesses with 21...axb6, Carlsen played the zwischenzug After the necessary Anand's a- and c-pawns remained isolated.
Black's weaker pawn structure was an important factor to Carlsen's initiative in this first decisive game of the match.