Benko Gambit: 5.bxa6 Bxa6

Benko Gambit: 5.bxa6 Bxa6

Definition

The sequence 5.bxa6 Bxa6 occurs in the Benko Gambit (also called the Volga Gambit) after the standard moves 1.d4 Nf6 2.c4 c5 3.d5 b5 4.cxb5 a6. White accepts Black’s pawn sacrifice with 5.bxa6, and Black immediately recaptures with the bishop, 5…Bxa6. The resulting position defines the accepted main line of the Benko, in which Black gives up a queenside pawn in exchange for enduring pressure on the a- and b-files, rapid piece activity, and long-diagonal control over g7–a1.

Typical Move Order

The most common continuation of this line is:

• 6.Nc3 g6
• 7.Nf3 d6
• 8.e4 Bxf1
• 9.Kxf1 Bg7, leading to a characteristic Benko middlegame.

Strategic Themes

• File Pressure. Black doubles rooks on the a- and b-files, tying White to the defense of b2 and a2.
• Queenside Majority vs. Extra Pawn. Although down a pawn, Black often gains it back or forces concessions by pushing …c4 and opening more lines.
• Piece Activity. The fianchettoed bishop on g7, together with a knight on c5 or d3, exerts long-range influence.
• Endgame Compensation. Even in simplified positions Black’s outside passed a-pawn can be dangerous.

Historical Background

The gambit was analyzed in the 1930s by Soviet players along the Volga River—hence the name Volga Gambit—but it was Hungarian-American GM Pal Benko who made 5…Bxa6 fashionable in top-level play during the late 1960s. Benko’s systematic use of the line in tournaments like Palma de Mallorca 1969 popularized its aggressive spirit and earned the opening his name in Western literature.

Illustrative Games

1. Pal Benko – Bobby Fischer, USA Championship 1963 Fischer neutralizes Benko’s own gambit, showing precise defensive technique with Black after 5…Bxa6 and eventually winning the endgame.
2. Garry Kasparov – Viktor Korchnoi, London 1986 Kasparov accepts the pawn with 5.bxa6 but fails to contain Black’s queenside pressure; Korchnoi draws comfortably.
3. Veselin Topalov – Viswanathan Anand, Sofia 2005 A modern heavyweight encounter where Anand’s dynamic 5…Bxa6 holds equal chances deep into a tactical middlegame.

Modern Usage

The line remains a popular weapon in blitz and classical chess alike:

• Repertoire choice of dynamic grandmasters such as Richard Rapport and Alexander Grischuk.
• Frequently appears in engine play; Stockfish evaluates the position as roughly equal (≈0.00) despite the material deficit, reflecting Black’s long-term compensation.

Interesting Facts & Anecdotes

• Some players call the pawn on a6 the most valuable pawn never to be captured, because Black’s play revolves around its ghost once 5…Bxa6 is played.
• Pal Benko reputedly offered the gambit to Fischer as Black in casual analysis sessions; Fischer’s initial skepticism turned to respect after he struggled to prove an edge.
• In the pre-computer era, the move 5…g6!? (delaying …Bxa6) was often considered risky; engines now show it is fully playable, enriching the theory surrounding 5.bxa6.