Sicilian, Chekhover, 4...a6

Sicilian

Definition

The Sicilian Defence is the chess opening that begins with the moves 1. e4 c5. Black immediately contests the center from the flank rather than mirroring White’s pawn to e5. The Encyclopaedia of Chess Openings (ECO) assigns codes B20–B99 to the many branches of the Sicilian, underscoring its enormous theoretical breadth.

Why Players Choose It

• Asymmetry from move one: Creates imbalanced pawn structures that promise winning chances for both sides.
• Rich theory: An ever-evolving body of analysis that rewards deep preparation.
• Practical results: Statistically the most successful reply to 1.e4 in master play.

Main Strategic Themes

Most Sicilian positions revolve around opposite-side castling and mutual pawn storms. Typical plans include:

• Black: …d6 or …e6 to shore up the d5 square, …a6/…b5 to expand on the queenside, piece pressure on the c-file.
• White: f2-f4 or g2-g4 pawn storms, sacrifices on b5 or d5 to rip open lines toward the Black king.

Major Families of Variations

1. Najdorf (…a6): 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6.
2. Dragon (…g6): 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6.
3. Scheveningen (…e6 & …d6): Often reached by transposition from the Najdorf.
4. Sveshnikov (…e5 early): 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5.
5. Accelerated Dragon (…g6 without …d6): Aims for …d5 in one move.
6. Closed Sicilian: White avoids an early d2-d4 and adopts a kingside fianchetto.

Historical Significance

Although first analyzed in the 16^th century by Italian masters, the Sicilian’s modern popularity exploded after World War II. Bobby Fischer famously called it “the Cadillac of openings,” and Garry Kasparov wielded it as his main weapon against 1.e4 in several World Championship matches.

Illustrative Game

[[Pgn|e4|c5|Nf3|d6|d4|cxd4|Nxd4|Nf6|Nc3|a6|Bg5|e6|f4|Be7|Qf3|Qc7|O-O-O|Nbd7|g4|b5|Bxf6|Nxf6|g5|Nd7|f5|Ne5|Qh3|Bxg5+|Kb1|exf5|Nxf5|Bxf5|Qxf5|Rc8|Bd3|Qc5|Rhf1|O-O|Nd5|Rce8|Qxg5|Re6|Qg3|Rc8|Rf4|Ng6|Rf5|Qc6|h4|Kh8|h5|Ne5|Qf2|Qb7|Rf1|b4|Qxd4|a5|h6|gxh6|Qe3|Rg8|Nf6|Rg6|Nd5|Qa6|Rxe5|dxe5|Rxf7|Rag8|Qa7|Rg1+|Qxg1|Rxg1+|Kc2|Qe6|Rf6|Qh3|Kb3|Rg3|Rf1|Rxd3+|Ka4|Qd7+|Kxa5|Qxa7+|Kxb4|Qb8+|Kc5|Qg8|Rxh6+|Kg7|Rc6|Qc1+|Kb5|Qb2+|Nb4|Rg6|Rxg6+|Kxg6|Na6|Qe2+|Kb6|Qxc4|b4|Qc8|Nc5|Qxc8|Na5|Kg5|Bd3|Kf3|Nb2+|Ke3|Nd1+|Kd2|Nf2|b5|e4|Ke3|e3+|Kf4|e2|b6|e1=Q|b7|Qe3+|Kg4|Qg5+|Kf3|Qg4+|Ke3|Qg3+|Kd4|Qf4+|Kb5|Qf1+|Kc6|Qf6+|Nd6|Qg2+|Kb6|Qf2+|Kc7|Qc5+|Kb8|Qg1|Nc8|Qg4|Na7|Qf4+|Kb7|Qg5|Nc6|Qd2|Kb8|Qb2#|fen|startpos|] ]

Tal – Fischer, Bled 1961, exhibits razor-sharp Najdorf tactics culminating in a classic opposite-side attack.

Interesting Facts

• The move order 1.e4 c5 accounts for roughly one out of every four master games beginning with 1.e4.
• Theorists jokingly divide chess history into “BS” and “AS” (Before and After Sicilian) because of how greatly it shifted opening theory.
• Anand used five different Sicilian subsystems as World Champion (Najdorf, Sveshnikov, Taimanov, Scheveningen, and the Hedgehog via English move orders).

Chekhover

Definition

The Chekhover Variation is a line of the Sicilian Defence characterized by an early queen recapture on d4: 1.e4 c5 2.Nf3 d6 (or 2…Nc6) 3.d4 cxd4 4.Qxd4. It is named after Russian master, composer, and endgame theorist Vitaly Chekhover (1908-1965).

Main Ideas

• Rapid development: White’s queen centralizes but also clears the c3-square for a knight and avoids the typical Nxd4 recapture.
• Surprise weapon: Because the queen appears early, many Sicilian specialists feel uncomfortable and may drift into inferior lines.
• Transpositional flexibility: Depending on Black’s reply (…Nc6, …a6, …Nf6, or …g6) White can steer toward Maroczy-bind, Alapin-style, or Open Sicilian structures.

Typical Continuations

1. 4…Nc6 5.Bb5: Pins the c6-knight and pressures d6.
2. 4…a6 5.c4: Leads to an English-type set-up with a spatial bind on d5.
3. 4…Nf6 5.Nc3: Transposes to some Open Sicilian main lines, but Black loses a tempo on d4.

Illustrative Miniature

Shirov – Timman, Wijk aan Zee 1996. An early queenside castle and rapid rook lifts give White a decisive attack.

Evaluation and Practical Value

The Chekhover is objectively sound but yields a small edge at best with perfect play. Its chief value lies in forcing Sicilian aficionados out of book on move four. Many grandmasters—especially rapid-play specialists like Alexander Grischuk—employ it as a low-maintenance anti-Sicilian weapon.

Anecdotes

• Vitaly Chekhover was better known for composing elegant knight endgame studies; friends teased that his opening line likewise features the knight “arriving late” (since the queen takes its natural d4 square).
• When Kasparov faced computers in the 1990s, his team briefly considered the Chekhover as an anti-engine sideline because early queen moves once confused evaluation algorithms.

4...a6

Definition

The notation 4…a6 refers to Black’s fourth move in the Najdorf Variation of the Sicilian Defence: 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 a6. The seemingly modest pawn push to the edge of the board has become one of the most heavily analyzed moves in chess history.

Purpose of the Move

• Prevents Nb5: Stops White’s knight or bishop from landing on b5 to harass the d6-pawn and c7-square.
• Prepares …e5 or …b5: By controlling b5, Black can later gain space on the queenside or strike in the center with …e5.
• Flexibility: Black has not yet committed the kingside pawns (…e6 or …g6), retaining the option to choose between Scheveningen, Dragon, or Classical structures.

Key Sub-Variations After 4…a6

1. 5.Bg5 (The Main Line): Leads to wild tactical battles featuring the famous Poisoned Pawn (…Qb6).
2. 5.Be3 (English Attack): White castles queenside and storms the kingside with g2-g4.
3. 5.Bc4 (Fischer–Sozin): Immediate pressure on f7; championed by Bobby Fischer.
4. 5.f3 (Anti-Najdorf): Sets up an eventual g2-g4 without committing the bishop.
5. 5.g3 (Fianchetto): A positional try aiming for long-term pressure on d6.

Historical Footprint

The move was popularized by Argentine grandmaster Miguel Najdorf in the 1940s. His resounding successes with it—coupled with the sharp, double-edged play it produces—made 4…a6 the gold standard of fighting defences against 1.e4. Kasparov relied on it in four separate World Championship matches (1986, 1987, 1990, 1995).

Iconic Encounter

Karpov – Kasparov, Linares 1994. Kasparov’s fearless adoption of the Poisoned Pawn showed that even a positional titan like Karpov could be dragged into tactical chaos after 4…a6.

Interesting Nuggets

• In databases, the move 4…a6 has been played by every World Champion from Tal through Carlsen—except Vladimir Kramnik, who preferred the Sveshnikov.
• The Najdorf is sometimes called “the Rolls-Royce of openings,” riffing on Fischer’s original Cadillac metaphor for the broader Sicilian.
• Engine era update: Modern engines at depth 40+ oscillate between 0.00 and +0.20 for most Najdorf main lines—proof that both sides can play for a win.

Practical Advice

Adopting 4…a6 requires serious theoretical upkeep, but it rewards the student with dynamic positions rich in tactical and strategic motifs. A sound repertoire tip is to learn one main line deeply (e.g., 5.Bg5 Nbd7 6.f4 Qc7) and one solid sideline (e.g., 5.g3) for variety.