Queen's Indian: Petrosian, 4...Ba6 5.Qc2

Queen’s Indian: Petrosian, 4...Ba6 5.Qc2

Definition

The Petrosian System with 4...Ba6 5.Qc2 is a branch of the Queen’s Indian Defense that arises after the moves 1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.a3 Ba6 5.Qc2. White’s rare fourth move 4.a3 prevents Black’s intended pin ...Bb4⁺. Black counters with 4...Ba6, eyeing the vulnerable c4-pawn and exerting pressure on the dark squares. White replies 5.Qc2, reinforcing c4, supporting an eventual e2–e4, and keeping flexible development options.

Typical Move Order

One common tabiya is:

• 1.d4 Nf6
• 2.c4 e6
• 3.Nf3 b6
• 4.a3 Ba6
• 5.Qc2 Bb7 (or 5...c5)
• 6.Nc3 d5 / c5 / Be7 depending on Black’s plan

Strategic Ideas for Both Sides

• White
  • Bolster the c4-pawn with Qc2 and potentially b2-b3.
  • Prepare e2–e4 to seize space in the center.
  • Exploit the fact that the bishop on a6 can become out of play if the c-file is closed.
• Black
  • Pressure c4 immediately with ...Ba6 and a timely ...c5.
  • Undermine the center with ...d5 or ...c5, depending on whether White commits to Nc3 or e2–e4.
  • Often re-routes the a6-bishop via b7 or c8 later if it proves ineffective.

Historical Background

The variation is named after the 9^th World Champion Tigran Petrosian, who introduced 4.a3 in the 1950s as a prophylactic idea against the thematic Queen’s Indian pin ...Bb4⁺. Petrosian’s deep positional style meshed perfectly with the slow-burn plans that arise here. Later, Garry Kasparov adopted the system frequently in the 1980s and 1990s, refining its attacking potential.

Canonical Games

1. Petrosian – Korchnoi, Candidates 1959
   Petrosian demonstrated how to blunt Black’s queenside pressure and transition into a favorable endgame.
2. Kasparov – Anand, Tilburg 1991
   Kasparov innovated with an early g4 thrust, showing the line can also lead to sharp attacks.
3. Vachier-Lagrave – Giri, Candidates 2020
   A modern heavyweight battle where both players followed contemporary theory deep into the middlegame before deviating.

Example Tabiya

One illustrative position after 1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.a3 Ba6 5.Qc2 Bb7 6.Nc3 d5:

Theoretical Assessments

• The line is judged to be sound and equal for Black, with rich, unbalanced play.
• Engines show a slight, stable +0.20 – +0.30 for White if the middlegame solidifies, but Black has full counterplay.

Interesting Facts & Anecdotes

• Petrosian once joked that 4.a3 was his “umbrella move” — shielding himself from the pin ...Bb4⁺ much like an umbrella shields from rain.
• Garry Kasparov scored several miniature wins in rapid events by surprising opponents who expected the sharper 4.g3 main line of the Queen’s Indian.
• Modern elite grandmasters occasionally revive the system as a low-theory alternative to the overloaded Queen’s Gambit Declined variations, aiming to reach fresh positions by move ten.

Practical Tips

• If you play White, memorize the key resource 7.cxd5! exd5 8.Bf4 (after ...d5 setups) to nullify Black’s bishop pair.
• As Black, be ready to switch the dark-squared bishop back to b7 or even c8 to avoid it getting trapped after c4-c5 closures.
• Move-order nuances matter: after 5.Qc2, playing 5...Bb7 is more flexible than 5...c5, which allows 6.d5! exd5 7.Nc3 with independent theory.