Sicilian Defence - Dragon and Najdorf

1. e4 c5
The Sicilian is the most popular and best-scoring response to White's first move 1.e4. "Indeed, most statistical surveys suggest that 1.d4 is the most successful first move for White, but only because 1...c5 scores so highly against 1.e4."[1] Indeed, New in Chess stated in its 2000 Yearbook that of the games in its database, White scored 56.1% in 296,200 games beginning 1.d4, but a full two percent lower (54.1%) in 349,855 games beginning 1.e4. "The main culprit responsible for this state of affairs" was the Sicilian, which held White to a paltry 52.3% score in 145,996 games.[2] One sixth (17%) of all games between grandmasters, and one quarter (25%) of the games in the Chess Informant database, begin with the Sicilian.[3]
Grandmaster John Nunn notes that the reason for the Sicilian Defence’s popularity "is its combative nature; in many lines Black is playing not just for equality, but for the advantage. The drawback is that White often obtains an early initiative, so Black has to take care not to fall victim to a quick attack."[4] The earliest recorded notes on the Sicilian Defence date back to the late 16th century by the Italian chess players Giulio Polerio and Gioachino Greco.[5][6]
By advancing the c-pawn two squares, Black asserts control over the d4-square and begins the fight for the centre of the board. The move resembles 1…e5, the next most common response to 1.e4, in that respect. Unlike 1...e5, however, 1...c5 breaks the symmetry of the position, which strongly influences both players' future actions. White, having pushed a kingside pawn, tends to hold the initiative on that side of the board. Moreover, 1...c5 does little for Black's development, unlike moves such as 1...e5, 1...g6, or 1...Nc6, which either develop a minor piece or prepare to do so. In many variations of the Sicilian Black makes a number of further pawn moves in the opening (for example, ...d6, ...e6, ...a6, and ...b5). Consequently, White often obtains a substantial lead in development and dangerous attacking chances.
Meanwhile, Black's advance of a queenside pawn has given him a spatial advantage there and provides a basis for future operations on that flank. Often, Black's pawn on c5 is traded for White's pawn on d4 in the early stages of the game, granting Black a central pawn majority. The pawn trade also opens the c-file for Black, who can place a rook or queen on that file to aid his queenside counterplay.
Grandmaster Jonathan Rowson recently considered why the Sicilian is the most successful response to 1.e4, even though 1...c5 develops no pieces, and the pawn on c5 only controls d4 and b4. Rowson writes, "To my mind there is quite a straightforward explanation. In order to profit from the initiative granted by the first move, White has to make use of his opportunity to do something before Black has an equal number of opportunities of his own. However, to do this, he has to make 'contact' with the black position. The first point of contact usually comes in the form of a pawn exchange, which leads to the opening of the position. ... So the thought behind 1...c5 is this: 'OK, I'll let you open the position, and develop your pieces aggressively, but at a price -- you have to give me one of your centre pawns.'"[7]

The Najdorf Variation is Black's most popular system in the Sicilian Defence. Najdorf's intention with 5...a6 was to prepare ...e5 on the next move to gain space in the centre; the immediate 5...e5?! is met by 6.Bb5+!, when Black must either play 5...Bd7 or 5...Nbd7. The former allows White to exchange off Black's light-squared bishop, after which the d5-square becomes very weak; but the latter allows 6.Nf5, when Black can only save the d-pawn by playing the awkward 6...a6 7.Bxd7+ Qxd7. In both cases, White's game is preferable.
Thus, by playing 5...a6, Black deprives White of the check on b5, so that ...e5 might be possible next move. In general, 5...a6 also prevents White's knights from using the b5-square, and helps Black create queenside play by preparing the ...b5 pawn push. This plan of 5...a6 followed by ...e5 represents Black's traditional approach in the Najdorf Variation. Later, Garry Kasparov also adopted the 5...a6 move order, but with the idea of playing ...e6 rather than ...e5. Kasparov's point is that the immediate 5...e6 (the Scheveningen Variation, discussed below) allows 6.g4, which is White's most dangerous line against the Scheveningen. By playing 5...a6 first, Black temporarily prevents White's g4 thrust and waits to see what White plays instead. Often, play will eventually transpose to the Scheveningen Variation.
Currently, White's most popular weapon against the Najdorf is 6.Be3. This is called the English Attack, because it was popularized by English grandmasters Murray Chandler, John Nunn and Nigel Short in the 1980s. White's idea is to play f3, Qd2, g4 and 0-0-0 in some order. Black can respond with 6...e6, 6...e5 or 6...Ng4; to prevent ...Ng4, White sometimes starts with 6.f3 instead. A related attacking idea for White is 6.Be3 e6 7.g4, known as the Hungarian Attack or the Perenyi Attack.
Formerly, 6.Bg5 e6 7.f4 was the main line of the Najdorf, when White threatens 8.e5 winning the pinned knight. Black can simply break the pin with 7...Be7, when White usually plays 8.Qf3 and 9.0-0-0. Alternative lines are 7...Qb6, the Poisoned Pawn Variation popularized by Fischer, and 7...b5, the Polugaevsky Variation, which has the tactical point 8.e5 dxe5 9.fxe5 Qc7! 10.exf6 Qe5+ winning the bishop in return for the knight.
White has other choices on the sixth move. 6.Be2 prepares to castle kingside and is a quieter alternative compared to 6.Be3 and 6.Bg5. Efim Geller was an early proponent of this move, after which Black can stay in "pure" Najdorf territory with 6...e5 or transpose to the Scheveningen with 6...e6. Other possibilities for White include 6.f4, 6.Bc4 (the Fischer Attack) and 6.g3. 6.h3, known as the Adams Attack (named after Weaver Adams), was used several times by Bobby Fischer.

In the Dragon Variation, Black fianchettoes a Bishop on the h8-a1 diagonal. It was named by Fyodor Dus-Chotimirsky in 1901, who noticed a resemblance between Black's kingside pawn structure (pawns on d6, e7, f7, g6 and h7) and the stars of the Draco constellation.[34] White's most dangerous try against the Dragon is the Yugoslav Attack, which goes 6.Be3 Bg7 7.f3 0-0 8.Qd2 Nc6, when both 9.0-0-0 and 9.Bc4 are played (see Sicilian, Dragon, Yugoslav attack, 9.Bc4 for the latter). This variation leads to extremely sharp play and is ferociously complicated, since the players castle on opposite wings and the game becomes a race between White's kingside attack and Black's queenside counterattack. White's main alternative to the Yugoslav Attack is 6.Be2, the Classical Variation.

By BispoMate