Benko Gambit - < 1700

A57: Benko Gambit

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The Benko Gambit is a chess opening characterised by the move 3...b5 in the Benoni Defense arising after:

1. d4 Nf6

2. c4 c5

3. d5 b5

Origin and predecessors

The idea of sacrificing a pawn with ...b5 and ...a6 is quite old. Karel Opočenský applied the idea against, among others, Gideon Ståhlberg at Poděbrady 1936, Paul Keres at Pärnu 1937, and Erich Eliskases at Prague 1937. Later the Mark Taimanov versus David Bronstein game at the Candidates Tournament, Zürich 1953, drew attention. Most of these games began as a King's Indian, with Black only later playing ...c5 and ...b5. Possibly the first to use the now-standard move order 1.d4 Nf6 2.c4 c5 3.d5 b5 was Thorvaldsson–Vaitonis, Munich Olympiad 1936.

The original name of the opening was the Volga Gambit, named after the Volga River because of an article about 3...b5!? by B. Argunow written in Kuibyshev (Samara since 1991), Russia, that was published in the second issue of 1946 of the magazine Schachmaty in USSR. The term is still widely used in Russian literature.

Beginning in the late 1960s, this opening idea was also promoted by Pal Benko, a Hungarian-American Grandmaster, who provided many new suggestions and published his book The Benko Gambit in 1974. The name Benko Gambit stuck and is particularly used in English-speaking countries.

Though "Volga Gambit" originally referred solely to the move 3...b5 (sometimes followed by an early ...e6), while Benko himself analyzed in his Batsford treatise solely what is now the main line, 3...b5 4.cxb5 a6, both the terms Benko Gambit and Volga Gambit are now used interchangeably or concurrently (for example, Volga–Benko Gambit). 

Theory

The main line continues with the moves 4. cxb5 a6 5. bxa6 Bxa6 followed by Black fianchettoing the f8-bishop. (Black players leery of the double-fianchetto system, where White plays g3 and b3, and fianchettos both bishops, have preferred 5...g6 intending 6.b3 Bg7 7.Bb2 Nxa6! The point is that it is awkward for White to meet the threat of ...Nb4, hitting d5 and a2, when Nc3 may often be met by ...Nfxd5 because of the latent pin down the long diagonal.) Black's compensation for the pawn takes several forms. Firstly, White (who is already behind in development) must solve the problem of developing the f1-bishop. After 6. Nc3 d6, if White plays 7.e4, then Black will play 7...Bxf1, and after recapturing with the king, White will have to spend time castling artificially with g3 and Kg2, as in the line 7....Bxf1 8.Kxf1 g6 9.g3 Bg7 10.Kg2. If White avoids this by fianchettoing the bishop, it will be in a rather passive position, being blocked by White's own pawn on d5.

Apart from this, Black also obtains fast development and good control of the a1–h8 diagonal and can exert pressure down the half-open a- and b-files. These are benefits which can last well into the endgame and so, unusually for a gambit, Black does not generally mind if queens are exchanged; indeed, such an exchange can often usefully remove the sting from a kingside attack by White.

Although the main line of the Benko is considered acceptable for White, there are various alternatives which avoid some of the problems entailed in the main line. The simplest is to just decline the gambit with 4.Nf3 or 4.a4. Another idea, which is popular at the grandmaster level as of 2004, is to accept the pawn but then immediately give it back with 4.cxb5 a6 5.b6. Another popular alternative is 5.e3.