Some of Black's alternatives 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!

Each phase may contain a number of variations ( lines arising from alternatives after the initial move of a phase ; in a two-mover, for example, variations in the post-key play begin on Black's first move ), but variations do not constitute distinct phases in themselves.

exf6 5. Nc3, doubling Black's pawns and giving him a hole on d5.

Kosten gives as Black's two main responses 3 ... Nf6 4. Bc4 ( 4. exf5 is also possible ) fxe4 5. Nxe5 d5 6. Nxd5!

By mid-1992, Black's first two albums had sold a combined 5 million copies.

White's apparent threat to win Black's e-pawn with 4. Bxc6 dxc6 5. Nxe5 is illusory — Black can respond with 5 ... Qd4, forking the knight and e4-pawn, or 5 ... Qg5, forking the knight and g2-pawn, both of which win back the material with a good position.

Black's most common reply is 4 ... d5 5. a3 Bxc3 + 6. bxc3 c5 7. cxd5 Nxd5, a position also reached from the Sämisch Variation.

Another approach for Black is to play 4 ... c5, after which White plays 5. d5 to keep his central pawns together reaches a Benoni-style position, and Black's main replies are 5 ... b5, 5 ... 0-0, 5 ... Bxc3 + and 5 ... Nh5.

This is often played by people unfamiliar with the Evans Gambit, but is arguably not as good as 5 ... Ba5, because 6. d4 attacks the bishop and narrows down Black's options as compared with 5 ... Ba5 6. d4.

Kxf7 5. Nxe5 + Nxe5 ( the Jerome Gambit ), an extremely dubious opening where White sacrifices two pieces in the hope of exposing Black's king and obtaining a mating attack.

The Cunningham Defence ( 3. Nf3 Be7 ) is Black's most aggressive option ; it can permanently prevent White from castling after 4. Bc4 Bh4 + 5. Kf1 ( else the wild Bertin Gambit, or Three Pawns ' Gambit, 5. g3 fxg3 6. 0-0 gxh2 + 7. Kh1, played in the nineteenth century ).

5 ... e5 is often considered something of an error on Black's part and 5 ... Bd7 can transpose to one of the more common variations, such as the Classical or Dragon, but there are also a number of independent lines.

After 3 ... cxd4, White occasionally plays 4. Qxd4, the Chekhover Variation, intending to meet 4 ... Nc6 with 5. Bb5 Bd7 6. Bxc6, when White hopes that his lead in development compensates for Black's bishop pair.

This plan of 5 ... a6 followed by ... e5 represents Black's traditional approach in the Najdorf Variation.

After 3. d4 cxd4 4. Nxd4, Black's most common move is 4 ... Nf6, when White usually replies 5. Nc3.

The Pixies ' musical style has been described as " an unorthodox marriage of surf music and punk rock, ... characterized by Black's bristling lyrics and hackle-raising caterwaul, Kim Deal's whispered harmonies and waspy basslines, Joey Santiago's fragile guitar, and the persistent flush of David Lovering's drums.

Ne7 12. Nexd5 cxd5 13. Nb5 is close to winning for White, and that the " old, discredited " 9 ... Bd6 ( rather than 9 ... Bc5 ) might be Black's best try, though still insufficient for equality.

Black can respond by either moving his queen or by playing ... h6, though the latter move weakens Black's kingside pawn structure.

If it is Black's move, the only legal move is 1 ... Kb7, which allows White to win with 2. Kd7 followed by queening the pawn on the next move.

Black's obvious defence, 1 ... exf1Q is answered by 2. Nf3 Kxf3 3. Rd2 #.

However, 40 ... Bxf6 would block Black's rook, allowing 41. Qf8 #, while 40 ... Rxf6 would block Black's bishop, allowing 41. Qg7 #.

Now, if 3 ... Kxc6, then 4. Kf4 stops Black's pawn after all, while if 3 ... h3 4. Kd6 allows White to promote his pawn.

Atkins originated an important defensive strategy in the Queen's Gambit Declined: an early ... Ne4 by Black in order to exchange off a pair of minor pieces and ease the pressure on Black's position.

Black's most flexible and frequently played response is 4 ... 0-0.

* The Karpov Variation, ( 7 ... dxc4 8. Bxc4 cxd4 9. exd4 b6 ) named after former World Champion Anatoly Karpov, is one of Black's most reliable defences to the Rubinstein System.

Black's usual choice is 7 ... Bb7, but 7 ... Ba6 is also possible to target the c-pawn, and 7 ... h6 8. Bh4 c5 and 7 ... c5 are sometimes played as well.

After 7 ... Bb7, White's most straightforward move is 8. f3 preparing e4, but Black can counter with 8 ... h6 9. Bh4 d5, when the pawn grab 10. cxd5 exd5 11. Bxf6 Qxf6 12. Qxc7 Ba6 is very dangerous for White because of Black's better development.

This is the Two Knights Defense where White has chosen the offensive line 4. Ng5, but Black's last move is risky ( other Black choices include 5 ... Na5, 5 ... Bg4, 5 ... b5, and 5 ... Nd4 ).

* 4. a3-The Sämisch Variation ( named after Fritz Sämisch ) is a direct attempt to refute Black's strategic concept, as White gives up a tempo and concedes doubled c-pawns to gain the bishop pair.

Black's best response is to transpose to the Fritz Variation with 6 ... Nd4, making another advantage of 6. Bf1 apparent — the bishop is not attacked as it would be if White had played 6. Be2.

* Paul Keres vs José Raúl Capablanca, AVRO Amsterdam 1938, French, Tarrasch, Open Variation, Main line ( C09 ), 1 – 0 Almost unpredictable jumps of the white knight slowly destroy Black's position.

In the late 1970s, however, Karpov, Kasparov and others found different methods to play the Exchange Variation with White, often involving an early Rb1 to remove the rook from the sensitive a1 – h8 diagonal, as well as attempting to hinder the development of Black's queenside.

The Najdorf Variation is Black's most popular system in the Sicilian Defence.

Apart from 4 ... Nf6, Black's most important moves are 4 ... e6 ( transposing to the Taimanov Variation ), 4 ... g6 ( the Accelerated Dragon ) and 4 ... e5 ( the Kalashnikov Variation ).

Black's major responses are 3 ... g6 preparing ... Bg7, 3 ... d6 preparing ... Bd7 ( a hybrid line that also arises from the Moscow Variation after 2 ... d6 3. Bb5 + Nc6 ), and 3 ... e6 preparing 4 ... Nge7.

It will frequently transpose into a standard line such as the Taimanov Variation or Paulsen Variation, or else White can play 3. c3 in the style of the Alapin Variation, where Black's queen may not be so well placed on c7.

A rarer option on Black's second move is 2 ... e6, with the aim of transposing to the Advance Variation of the French Defence after 3. d4 d5 4. e5.

Grandmaster Larry Kaufman, in his book The Chess Advantage in Black and White, notes that the Hanham Variation aims to maintain Black's pawn on e5, analogously to closed lines of the Ruy Lopez, and opines that " it would be quite popular and on a par with the major defenses to 1. e4, except for the annoying detail that Black can't actually reach the Hanham position by force.

The Brooklyn Variation involves retreating Black's knight back to g8.

A popular setup from White to prevent Black's plan is the Voronezh Variation ( named after the city Voronezh in Russia, where the line was invented, by players such as Grigory Sanakoev ).

The statistics presented by Cox show the Chase Variation scoring poorly for White, with all of Black's main defenses scoring at least 50 %.

This usually transposes to positions arising from 3 ... Nf6, and has the advantage, from Black's standpoint, of avoiding the insidious pressure of the main lines in the Exchange Variation arising after 3 ... Nf6 4 cxd5 exd5 5 Bg5 with an annoying pin.