Benko Gambit: 4.cxb5 a6 5.b6 e6

Benko Gambit: 4.cxb5 a6 5.b6 e6

Definition

This line is a sideline of the Benko Gambit (also called the Volga Gambit). After the standard moves
1. d4 Nf6 2. c4 c5 3. d5 b5
White accepts the gambit pawn with 4. cxb5, and Black continues 4...a6. Instead of allowing Black to recapture on b5 with ...axb5, White pushes the pawn further with 5. b6. Black’s reply 5...e6 defines this variation: Black ignores the b-pawn for the moment and strikes at the dark-squared center, aiming for ...exd5 followed by ...d6 or ...g6, leading to Benoni- or Catalan-flavored structures.

How It Is Used in Play

• For Black: The move 5...e6 transforms the game from a pure Benko into a hybrid Benko-Benoni. Black hopes to undermine White’s center, open dark-squared diagonals for the queen and bishop, and eventually put pressure on the long a1–h8 diagonal once the b6-pawn falls.
• For White: The advanced b6-pawn cramps Black’s queenside, claiming the a7-square and often forcing Black to waste time recapturing it. White usually develops with Nc3, g3, Bg2, Nf3, and may delay e4 until the center is clarified.

Strategic Ideas and Significance

• Queenside space vs. central play: White’s pawn on b6 restricts Black’s queenside pieces (especially the light-squared bishop and the rook on a8). Black counters by striking in the center with ...e6 and later ...d5 or ...exd5, aiming to prove that the b-pawn is over-extended.
• Piece activity: Unlike mainstream Benko lines where Black fianchettoes with ...g6 at once, here Black may leave the king’s bishop on e7 or d6, obtaining quicker kingside castling and more central pressure.
• Pawn structure flexibility: If Black succeeds in playing ...exd5 followed by ...d6, the resulting structure resembles a Modern Benoni in which Black has already encouraged b6, giving both sides original chances.
• Endgame prospects: Should the position simplify, the passed b-pawn can become decisive for White; conversely, if Black wins it without concessions, the two central pawns (e- and d-files) may roll.

Historical Background

The idea of 5...e6 gained practical popularity in the late 1970s and early 1980s when grandmasters such as Vladimir Tukmakov and Alexander Beliavsky explored alternatives to the heavily analyzed main lines with 5...axb5 6. Nc3. Modern specialists—including Aleksei Shirov and Pentala Harikrishna—occasionally adopt it as a surprise weapon to avoid the deep positional theory of the classical Benko.

Typical Plans for Both Sides

• White
  1. Maintain the pawn on b6 as long as possible.
  2. Develop quickly: g3, Bg2, Nc3, Nf3, 0-0.
  3. Prepare e4 to seize central space once Black has exchanged on d5.
  4. Use the a-file and the a4-square for later rook activity if the a-pawn advances.
• Black
  1. Play ...exd5 at the right moment, often followed by ...d6 or ...d5.
  2. Pressure the b6-pawn with ...Qxb6 or ...Nbd7–b6.
  3. Fianchetto with ...g6 only after central tension is resolved, or keep the bishop flexible on e7/d6.
  4. Seek dynamic counterplay on the dark squares—especially e5 and c5.

Illustrative Game

Below is a condensed example showing typical ideas in action.

• After 17...e4 White retains the b-pawn but Black’s pieces are active.
• The struggle revolves around whether the passer outweighs Black’s central pressure.

Interesting Facts & Anecdotes

• The move 5...e6 was once regarded as “anti-Benko”—some databases still classify it under Old Benoni ECO codes (A56-A57) rather than Benko (A58-A59).
• Benko himself never played this exact variation, preferring the classical ...axb5 lines, but he praised the concept in later annotations for giving Black “a second way to sacrifice the b-pawn.”
• In rapid and blitz, grandmasters sometimes play 5...e6 as a psychological weapon, counting on opponents to be less booked-up compared to the labyrinthine main lines beginning 5...axb5 6. Nc3.

Summary

The 4.cxb5 a6 5.b6 e6 line offers Black an alternative gambit: instead of immediate queenside compensation, Black gambles on quick central counterplay while the loose b6-pawn serves as both a target and White’s most valuable asset. Understanding the delicate balance between the passed pawn and Black’s activity is the key to mastering this dynamic sideline of the Benko Gambit.