Benko Gambit Declined Sosonko Variation
Benko Gambit Declined, Sosonko Variation
Definition
The Benko Gambit Declined, Sosonko Variation is a branch of the Benko (or Volga) Gambit in which White chooses not to accept Black’s pawn sacrifice on b5. After the moves 1. d4 Nf6 2. c4 c5 3. d5 b5 4. Nf3, White simply develops a piece instead of playing 4. cxb5. The line is named after the Soviet-Dutch grandmaster Gennadi Sosonko, who adopted it frequently in the 1970s–80s and demonstrated its positional soundness.
Typical Move Order
The opening sequence most commonly associated with the Sosonko Variation is:
- 1. d4 Nf6
- 2. c4 c5
- 3. d5 b5 (the Benko Gambit offer)
- 4. Nf3 (Sosonko’s move, declining the pawn)
Black usually replies with 4…g6 (transposing to Benko-style fianchetto set-ups) or 4…e6 (preparing …exd5 and …d6 in a King’s Indian structure).
Strategic Themes
- White’s approach: By keeping the pawn on b5 defended, White preserves a spatial plus in the center, aims for rapid kingside development (e2-e4, Nc3, Bd3), and can later undermine the queenside with a2-a4.
- Black’s compensation: Even without the gambit pawn, Black strives for typical Benko pressure: …g6, …Bg7, …d6, …0-0, and an eventual …a6 or …bxc4 to prise open the a- and b-files.
- Piece placement: White often maintains a knight on c3 and bishop on g5 or f4 to hinder …e6-e5 or …d7-d6 breaks; Black’s knight commonly reroutes from f6 to d7 via …Nbd7 to support …a6.
Historical Background
The variation gained prominence after Sosonko defeated several grandmasters with it in the mid-1970s. His 1975 Wijk aan Zee game against Vlastimil Hort, for example, featured a model queenside clamp that left Black’s pawn sacrifice unfulfilled. Modern engines confirm that White’s score in this line is higher than in the main accepted Benko, making 4.Nf3 a respected practical weapon.
Model Game Snapshot
Moves 1–10 from a typical encounter:
White has finally captured on b5, but only after securing central control and preventing Black’s quick counterplay. Black still retains the typical Benko bishop on g7 and open files, but the delayed capture reduces the gambit’s sting.
Typical Plans for Both Sides
- White
- Break with a2-a4 or c4-cxb5 at a moment of their choosing.
- Play e2-e4 to seize the center, sometimes supported by Re1 and Nc3-d2-c4.
- Exchange dark-squared bishops with Bg5 to diminish Black’s long-diagonal pressure.
- Black
- Fianchetto the king’s bishop and castle quickly.
- Prepare …a6 and …bxc4 (or …b4) to open lines regardless of material balance.
- Pressure the e4-square; many lines feature …Nbd7-b6, …Ba6, and …Rfb8.
Interesting Facts & Anecdotes
- The ECO code for the Sosonko Variation is A57.
- Although called “declined,” White sometimes ends up taking the pawn later when it is positionally convenient—earning the quip that Sosonko’s line is a “Benko Deferred.”
- Magnus Carlsen used 4.Nf3 in rapid play (Carlsen – Svidler, World Blitz 2017), indicating its continued relevance at the elite level.
- Sosonko once joked in an interview that declining the gambit let him “sleep at night” because he never had to face the well-prepared Benko specialists on their favorite turf.
Practical Advice
If you are a Benko player, expect 4.Nf3 from opponents who prefer positional grinds over tactical melees. Study both 4…g6 and 4…e6 systems; each has different pawn-break timings. Meanwhile, as White, remember that flexibility is key: do not rush cxb5, and be ready to meet …bxc4 with Bxc4, keeping your center intact.