Benko Gambit

The Benko Gambit, called the Volga Gambit in much of Eastern Europe, arises when Black meets 1. d4 Nf6 2. c4 c5 3. d5 by striking at c4 with 3...b5. The pawn buys long-term queenside play rather than a direct attack. Once the a- and b-files open, Black's rooks and queen target White's a- and b-pawns, while the bishop fianchettoed on g7 sweeps the long diagonal toward a1. Because these assets survive simplification, Black, unusually for a gambit player, rarely objects to a queen trade, and in endgames the black king can walk toward the center along the dark diagonal.

Taking with 4. cxb5 is by far the most common reply. The accepted main line continues 4...a6 5. bxa6 Bxa6, followed by ...d6, ...g6 and ...Bg7. White's chief practical problem is the f1-bishop: after 6. Nc3 d6 7. e4 Bxf1 8. Kxf1 g6 9. g3 Bg7 10. Kg2 the king has to castle artificially. The Fianchetto Variation, 6. Nc3 d6 7. Nf3 g6 8. g3, keeps castling rights, but the g2-bishop is blunted by White's own pawn on d5; 8. Nd2 in that position is the Nd2 Variation. Some Black players wary of White's double fianchetto prefer 5...g6, recapturing on a6 later with the knight.

White can also keep the first pawn and refuse the second. The older 5. e3 and the more recent 5. f3 axb5 6. e4 aim for central play, while 5. b6 gives the pawn back at once to keep the queenside files closed. The Zaitsev System, 5. Nc3, leads after 5...axb5 6. e4 b4 7. Nb5 to the Nescafe Frappe Attack, in which the knight goes forward to b5 rather than retreating.

Declining at move four lets Black gain queenside space with ...b4, taking c3 away from White's knight. 4. Nf3 is the main declined line, and 4...g6 often heads back toward accepted structures. The Sosonko Variation, 4. a4, provokes either 4...bxc4, which leads to sharp and little-explored play, or the closed 4...b4. The quiet 4. Nd2 meets 4...bxc4 with 5. e4, intending to win the pawn back with the bishop. 4. b3 weakens the long diagonal and has done badly in practice. 4. e4 is the Hjørring Countergambit.

Boris Argunov analyzed 3...b5 4. cxb5 a6 in a 1946 article in Shakhmaty v SSSR, written in Kuibyshev on the Volga, which gave the gambit its Eastern European name. Pal Benko promoted it from the late 1960s and published The Benko Gambit in 1974. Kasparov, Anand, Topalov, Tal and Carlsen have all played it, and it is popular at club level for the winning chances it gives Black. In online databases Black scores slightly better than White, although engines give White a slight edge.