Sicilian Defense: Closed, Korchnoi Defense

Sicilian Defense: Closed

Definition

The Closed Sicilian is a branch of the Sicilian Defense that arises after 1. e4 c5 2. Nc3, with White intending to avoid the sharp, open central confrontations typical of the main-line Open Sicilian (2. Nf3 followed by 3. d4). Play usually continues 2…Nc6 (or 2…d6) 3. g3, heralding a kingside fianchetto and a slower, maneuvering struggle.

Typical Move Order

A “pure” Closed Sicilian can start in a variety of ways, but the most common sequence is:

1. e4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3 d6 6. f4.

Strategic Themes

• Slow, flank-based attack: White castles short, plays Nf3, Be3, Qd2, and often launches a pawn storm with f4-f5, h3, g4, and sometimes f5-f6, aiming at Black’s kingside dark squares.
• Black’s counterplay: Black normally challenges the center with …e6 and …d5 or strives for queenside play with …b5 and …b4. Dark-square control, especially the d4-square, is critical.
• Piece maneuvers: Knights frequently re-route (Nb1–d2–f1–e3/g3 for White or …Ng8–f6–e8–c7/b6 for Black) to improve their posts before concrete operations begin.

Historical Significance

The Closed Sicilian was fashionable in the 1960s and 70s as a practical weapon to avoid the voluminous Sicilian theory exploding after Fischer. Players such as Boris Spassky, Bent Larsen, and more recently Shakhriyar Mamedyarov have used it to good effect.

Illustrative Example

This fragment shows the typical setup: White’s f-pawn advances, pieces point toward g7, and Black eyes the key d4 outpost.

Famous Games

• Spassky – Fischer, Candidates Final (game 5), 1968 — a textbook kingside pawn storm culminating in a direct attack.
• Mamedyarov – Topalov, Tal Memorial 2008 — modern handling with rapid f4-f5 followed by g4.

Interesting Facts

• Because the Closed Sicilian often features a kingside fianchetto from both sides, commentators sometimes joke that “the bishops look at one another all game without ever exchanging.”
• In computer chess, engines once underestimated White’s long-term space grab, but as evaluation algorithms improved, the line’s strategic richness became more appreciated.

Korchnoi Defense

Definition

The Korchnoi Defense is a flexible anti-d4 system defined by the moves 1. d4 e6 2. Nf3 c5!? (ECO A40). By delaying an early …d5, Black keeps multiple transpositional possibilities open — including English Defense structures with …b6, Tarrasch-French set-ups after …d5, or even a Benoni if White pushes d4–d5. The line is named after Viktor Korchnoi, who employed it regularly in the 1970s and 80s to unbalance quieter Queen’s-Pawn positions.

Main Ideas

• Early …c5 strike: Black challenges the center before committing the king’s knight; this can induce structural weaknesses or transpose into less-explored terrain.
• Elastic pawn structure: Depending on White’s reply (3. e3, 3. d5, 3. c3, etc.) Black may adopt
  1. …Nf6 and …d5 (French-style),
  2. …b6 and …Bb7 (English Defense), or
  3. …exd5 followed by …d6 (Benoni).
• Practical surprise value: Because theory is thinner than in mainstream Queen’s-Pawn openings, the onus is on White to choose the correct plan.

Typical Move Orders

a) 1. d4 e6 2. Nf3 c5 3. e3 Nf6 4. c4 d5  — transposes to the Tarrasch French with colors reversed.

b) 1. d4 e6 2. Nf3 c5 3. d5!? exd5 4. Qxd5 Nf6 5. Qd1  — a quirky line in which Black obtains active piece play against White’s slightly undeveloped army.

c) 1. d4 e6 2. Nf3 c5 3. c4 Nf6 4. Nc3 b6  — English Defense set-up.

Historical & Strategic Significance

Korchnoi first unveiled the idea at top level against Anatoly Karpov in the 1974 Candidates Final. Its leitmotif—meeting 1. d4 with flexibility and early counter-punches—fit Korchnoi’s combative style. Although never as popular as mainstream Indian defenses, it remains a viable surprise weapon and is occasionally adopted by dynamic players such as Alexander Grischuk and Richard Rapport.

Illustrative Mini-Game

After a few natural developing moves, the game has reached a dynamic French-type IQP structure, but with the kings safely castled and both players holding trumps on different wings.

Notable Games

• Karpov – Korchnoi, Candidates Final 1974, game 2 — Korchnoi equalized effortlessly and later won, demonstrating the opening’s robustness.
• Grischuk – Rapport, Biel 2017 — a modern illustration where Black steered the position into a Benoni-style middlegame and achieved counterplay on the dark squares.

Interesting Facts

• The initial move order 1. d4 e6 keeps open the possibility of transposing into a French Defense if White switches to 2. e4, giving the Korchnoi practitioner an additional psychological edge.
• Because ECO tablebases place it in the “A00–A40” codes rather than the French (C00–C19) or Benoni (A56–A79), databases sometimes index Korchnoi’s own games under three different opening families!
• Viktor Korchnoi recommended the line in his autobiography “Chess Is My Life,” calling it “an anti-d4 Sicilian” – a nod to the reversed pawn structure.