Kings Indian Defense Petrosian Variation Stein Defense
King's Indian Defense
Definition
The King's Indian Defense (KID) is a hyper-modern opening that arises after the moves 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6. Black allows White to occupy the center with pawns, intending to strike back later with pawn breaks such as …e5 or …c5 and active piece play. ECO codes: E60–E99.
Typical Move-Order & Main Branches
- 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 0-0 (Black completes development before challenging the center.)
- The critical decision is whether Black plays …e5 (Orthodox lines) or …c5 (Fianchetto & Makogonov lines).
- White chooses among systems such as the Classical (6.Be2), Sämisch (5.f3), Fianchetto (g3), Four-Pawns Attack (f4), and the Petrosian (7.d5) covered below.
Strategic Themes
- Counter-punch: Black aims for …e5 or …c5, …f5, and piece activity, often sacrificing space for dynamic potential.
- Pawn Structure: A locked center (d4–e4 vs. d6–e5) leads to opposite-side play—White on the queenside, Black on the kingside.
- Piece Placement: Knights often maneuver (Nf6–e8–c7–e6), bishops remain powerful on long diagonals, and the dark-squared bishop is the pride of Black’s position.
Historical Significance
Popularized by Soviet greats such as David Bronstein and Isaac Boleslavsky in the 1940s, the KID became a mainstay of World Championship matches. Bobby Fischer, Garry Kasparov, and more recently Hikaru Nakamura and Ding Liren have all used it as a principal weapon against 1.d4.
Illustrative Mini-Game
The diagram (after 7…a5) shows the starting point of the Stein Defense—note the locked center and opposite-wing ambitions.
Interesting Facts
- The KID’s reputation swings in cycles; whenever theory declares it “refuted,” a new defensive resource is found.
- Garry Kasparov scored many brilliancies with the KID, calling it “the most aggressive answer to 1.d4.”
- The opening’s ECO chapters (E60-E99) are the longest for any single defense, reflecting its immense complexity.
Petrosian Variation (King's Indian Defense)
Definition
The Petrosian Variation arises in the Classical System of the KID after 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 0-0 6. Be2 e5 7. d5. Named after Tigran Petrosian, World Champion 1963-69, the line features White locking the center with d5 to clamp down on Black’s …f5 break and gain space on the queenside.
Strategic Ideas
- Space Advantage: The pawn on d5 gives White room on the queenside (c- and b-files) to prepare c5 or b4.
- Prophylaxis: Petrosian’s concept was to restrict Black’s typical kingside pawn storms by limiting piece mobility.
- Flexibility: White can castle either side and choose plans such as a4–b4, Nd2–c4, or Be3–Qd2–Bh6.
- Long-term Battle: Because the position is closed, maneuvering skill often outweighs concrete calculation.
Key Black Replies
- 7…a5 – The Stein Defense (see next section).
- 7…Na6 – The Ponomariov System, attempting …Nc5 and …a5.
- 7…Nbd7 – The Gligorić System, aiming for …Nh5 and …f5.
- 7…exd4 – The Smyslov Variation, opening the center immediately.
- 7…c6 – A modern idea championed by Grischuk, preparing …b5.
Historical Note
Petrosian unveiled the system in the 1950s as a safe, strategic way to combat the razor-sharp KID. Ironically, his future rival Leonid Stein invented the most dynamic antidote—7…a5—which now bears his name.
Model Game
Petrosian vs. Bronstein, Moscow 1966 After 7.d5 a5 8.Bg5 h6 9.Bh4 Na6 10.Nd2, Petrosian eventually neutralized Black’s counterplay and won in a queen-side breakthrough, illustrating the enduring soundness of his concept.
Interesting Tidbits
- The variation was fashionable again in the 2010s thanks to Vladimir Kramnik, who used it to defeat Levon Aronian in Wijk aan Zee 2011.
- Because the center is locked, endgames often arise where the “bad” light-squared bishop can suddenly become powerful after a timely f3–f4 break.
Stein Defense (against the Petrosian Variation)
Definition & Move-Order
The Stein Defense is Black’s most dynamic response to the Petrosian system and begins immediately after White plays 7.d5:
7…a5 8.Bg5 h6 9.Bh4 Na6 (Leonid Stein’s original move sequence)
The key idea is the immediate pawn thrust …a5, challenging White’s queenside expansion and introducing tactical possibilities on both flanks.
Strategic Essence
- Counter-space: …a5 prevents b4, fixes the a- and b-pawns, and secures the a5-square for a knight or rook.
- Flexible Knight Routes: …Na6–c5 eyes the d3 square and supports …f5 breaks.
- Kingside Play Preserved: The usual KID themes (…f5, …g5, …Nh5) remain on the table, giving Black a “double-edged” position.
- Tactics on the a-file: Black often sacrifices the a-pawn to open lines or to place a rook on a3 via …Ra6!
Historical Background
Soviet GM Leonid Stein (1934-1973), one of the most feared attackers of his day, introduced the line in the early 1960s. His successes against both Petrosian and Spassky popularized the system, which soon earned its own ECO sub-code (E92).
Classic Example
Petrosian – Stein, USSR Championship, Tbilisi 1966
Moves: 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.d5 a5 8.Bg5 h6 9.Bh4 Na6 10.Nd2 Qe8 …
Stein unleashed a fierce kingside assault crowned by the exchange sacrifice …Rxa3!, eventually forcing resignation on move 39.
Theoretical Status
Modern engines rate the position as roughly equal, but practical tests still show rich winning chances for Black. Top protagonists include Teimour Radjabov and Richard Rapport.
Interesting Facts
- The immediate 7…a5 was controversial when first played—contemporaries thought Stein had “forgotten theory.” He hadn’t; he was rewriting it.
- Some databases list the line as the “Petrosian System, Stein Attack”—a rare case where the defender’s name is attached to the word “Attack.”
- Because the pawn on a5 can become weak, many grandmasters delay castling to keep the rook flexible—another subtlety introduced by Stein.