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The Sicilian Defence is a chess opening which begins with:

1.e4 c5

This is the most popular response to 1.e4 at the master level. Black immediately fights for the centre, but by attacking from the c-file (instead of mirroring White's move) he creates an asymmetrical position that leads to complicated situations. Typically, White has the initiative on the kingside while Black obtains counterplay on the queenside, particularly on the c-file after the exchange of Black's c-pawn for White's d-pawn.

The opening was named by Gioacchino Greco in the 17th century.

Contents 1 Open Sicilian 1.1 2...d6 1.1.1 Dragon 1.1.2 Najdorf 1.1.3 Classical 1.1.4 Scheveningen 1.1.5 Moscow 1.1.6 Other 1.2 2...Nc6 1.2.1 Sveshnikov 1.2.2 Accelerated Dragon 1.2.3 Rossolimo 1.2.4 Other variations 1.3 2...e6 1.3.1 Taimanov 1.3.2 Kan 1.4 Other moves in the Open Sicilian 2 Other systems 3 ECO codes

Open Sicilian

The most common Sicilian variations start with the moves 1.e4 c5 2.Nf3, when there are three main continuations for Black: 2...d6, 2...Nc6, and 2...e6. White then plays 3.d4, when black replies with 3...cxd4. The resulting position is one of the most complex in modern chess practice, as white's advantage in development and space are counterbalanced by black's central pawn majority and open c file.

2...d6

The most common move, Black's move opens up for his bishop and defends the e5 square. Play usually continues 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 when Black usually winds up playing the Dragon (5...g6), Najdorf (5...a6), Classical (5...Nc6), or Scheveningen (5...e6).

Dragon

Main article: Dragon Variation

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Black can adopt a variety of set-ups, among them the Dragon variation, which begins

1.e4 c5

2.Nf3 d6

3.d4 cxd4

4.Nxd4 Nf6

5.Nc3 g6

In this variation, Black fianchettoes a Bishop on the h8-a1 diagonal. This is called the "Dragon" variation, by one account because Black's kingside pawn structure looks like a dragon. Another possible reason for the name is that a very aggressive middlegame usually develops following opposite-side castling.

Najdorf

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Main article: Sicilian Najdorf

The most popular Sicilian system is the Najdorf, which begins

1.e4 c5

2.Nf3 d6

3.d4 cxd4

4.Nxd4 Nf6

5.Nc3 a6

White plays a variety of moves here, including 6.Bg5, 6.Be2, 6.Be3, Bobby Fischer's preferred response 6.Bc4, 6.f3, 6.f4, 6.g3, and, rarely, 6.h3 or even 6.Rg1, preparing 7.g4.

Classical

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After

1.e4 c5

2.Nf3 d6

3.d4 cxd4

4.Nxd4 Nf6

5.Nc3 Nc6,

the so-called "Classical" Sicilian arises, featuring sound natural development from both sides. Both sides have brought out their knights to the best squares. White usually continues with 6.Bg5 (the Richter-Rauzer Variation), which aims to weaken the Black kingside with a timely Bxf6 when Black often must respond with the weakening ...gxf6. In return, Black will enjoy a useful majority of pawns in the centre. Another popular variation is 6.Bc4, the Sozin Variation, which brings the bishop to an aggressive square, and allows white to castle on either the kingside or the queenside (the hyper-aggressive Velimirovic Attack). The Sozin Variation was a favorite of Bobby Fischer. Less popular moves are 6.Be2, 6.Be3, 6.f3, 6.g3, and 6.f4.

Scheveningen

1.e4 c5

2.Nf3 d6

3.d4 cxd4

4.Nxd4 Nf6

5.Nc3 e6

The Scheveningen gives Black a small defensive centre, but which can be useful in preventing a White assault there while Black concentrates on the queenside. A surprising but dangerous attempt for White is the Keres Attack, beginning with 6. g4.

Moscow

1.e4 c5

2.Nf3 d6

3.Bb5+

This is a simplifying line which is a fairly popular alternative if White wants to avoid the mainline theory. This variation was played by Garry Kasparov in the online game Kasparov versus The World.

Other

White can also keep his options open with the "Chameleon System" championed by Soltis and others, a typical line of which runs 2. Nc3 d6 3. Nge2, keeping Black guessing whether White will play a Closed Sicilian with 4.g3 or transpose to a standard Open Sicilian with 4. d4.

2...Nc6

By playing 2...Nc6 Black develops the knight to a natural square. Play often transposes to the Classical variation given under 2...d6, but there are some major alternatives.

Sveshnikov

1.e4 c5

2.Nf3 Nc6

3.d4 cxd4

4.Nxd4 Nf6

5.Nc3 e5

This variation (pioneered by Evgeny Sveshnikov) has become very popular in master level chess. Black's 5...e5 looks very illogical, making the d6 pawn backward and potentially weak, and the d5 square is now a hole in the Black position. In return Black gets a foothold in the centre and White's knight is forced to spend a lot of time to find a safe square.

Accelerated Dragon

1.e4 c5

2.Nf3 Nc6

3.d4 cxd4

4.Nxd4 g6

The Accelerated Dragon features an early ...g6 from Black. Black avoids the Yugoslav attack, but since White has not been forced to play Nc3 yet, the option of playing c4 (the Maroczy Bind) remains available.

Rossolimo

1.e4 c5

2.Nf3 Nc6

3.Bb5

Like the Moscow variation, White plays an early Bb5, usually with the intention of trading it for the c6-knight and giving Black doubled pawns. Blacks most usual continuation is to quickly develop by 3...g6, although moves like 3...Qc7, 3...Qb6 and 3...e6 are also possible.

Other variations

Sometimes Black plays such moves as an early ...Qb6 (e.g. after 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Qb6 which brings more attackers against the d4 square.

2...e6

This move tends to lead to more defensive formations. Transpositions to the Scheveningen are quite common, but there are some other variations which are also popular.

Taimanov

1.e4 c5

2.Nf3 e6

3.d4 cxd4

4.Nxd4 Nc6

The Taimanov is named after Mark Taimanov. Black develops the knight to a natural square and keeps some options open on the kingside. Like other variations of the Sicilian where Black does not play an early ...Nf6 forcing Nc3, White does have the option of establishing a grip on the centre by 5.c4.

Kan

1.e4 c5

2.Nf3 e6

3.d4 cxd4

4.Nxd4 a6

By playing 4...a6, Black prevents the White knight from jumping to b5, as well as preparing an eventual ...b5 advance.

5.Nc3 Qc7

Here white can continue by playing Be2,or Bd3(the most common response) followed by castling kingside with using the f-pawn to start a kingside attack.

Other moves in the Open Sicilian

After 1.e4 c5 2.Nf3, Black has some other options including:

• 2...Nf6 is the Nimzowitsch variation which allows White to chase the knight by 3.e5. It bears some similarity with the Alekhine Defense.
• 2...g6 is the Hyper-Accelerated Dragon, bearing strong resemblance to the "normal" Accelerated Dragon.
• 2...a6 is the O'Kelly Variation.

Other systems

To avoid giving Black this wide choice of systems, White can adopt a number of so-called "anti-Sicilian" lines, including:

• 2.Nc3 followed by g3 (the Closed Sicilian).
• 2.Nc3 followed by f4 (the Grand Prix Attack), a typical line of which runs 2.Nc3 Nc6 3.f4 g6 4. Nf3 Bg7 5. Bc4 e6 6.f5.
• 2. c3 (the Alapin Sicilian).
• 2. d4 cxd4 3. c3 (the Smith-Morra Gambit).
• 2. b4?! (the Wing Gambit).
• 2. g3 (which may transpose to the Closed Sicilian but offers other options -- such as 2...d5 for Black, and a centre buildup with c3 and d4 for White).
• 2. c4.
• 2. b3.
• 2. f4 An ambitious attempt to achieve a more flexible Grand Prix setup by White is 2. f4. This has the disadvantage of allowing 2...d5 which is playable as a pawn sacrifice (3.exd5 Nf6), however White may refuse this with 3.Nc3, leading to the so-called Toilet Variation, named after the inventor's original place of inspiration.

ECO codes

The Encyclopaedia of Chess Openings has given all the codes from B20 to B99 to the Sicilian, giving this opening more codes than any other opening. In general these guidelines apply:

• The B20 series (B20-B29) covers the sidelines where White does not play 2.Nf3. B27 to B29 however cover 2.Nf3 variations, B27 has rare second move responses from Black, B28 covers the O'Kelly Variation (2...a6) while B29 covers the Nimzovitsch Variation (2...Nf6).
• The B30 series covers the lines beginning 1.e4 c5 2.Nf3 Nc6 and which do not have an early ...d6 (which would usually put the opening into the B60 series). The most important variations here are the Rossolimo, Kalashnikov, Sveshnikov and Accelerated Dragon.
• The B40 series covers the lines beginning 1.e4 c5 2.Nf3 e6, most importantly the Taimanov and Kan variations.
• The B50 series covers the sidelines of 1.e4 c5 2.Nf3 d6. Here is the Moscow Variation (3.Bb5+), Chekhover Variation (3.d4 cxd4 4.Qxd4) and some other rare lines such as 3.d4 cxd4 4.Nxd4 Nf6 5.f3. The codes B56 to B59 also cover some lines of the Classical, most importantly the Sozin Variation.
• The B60 series covers the Richter-Rauzer Variation of the Classical Sicilian.
• The B70 series covers the normal (unaccelerated) Dragon Variation.
• The B80 series covers the Scheveningen Variation.
• The B90 series covers the Najdorf Variation.