Petrov's Defence

For other uses, see Petrov.

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Petrov's Defence (sometimes spelled Petroff's) is the chess opening

1.e4 e5

2.Nf3 Nf6

Though this symmetrical response has a long history, it was first popularized by Alexander Petrov — a Russian chess player of the mid-19th century. In recognition of the early investigations by the Russian masters Petrov and Carl Jaenisch, this opening is called the Russian Game in some countries.

The Petrov has a reputation of being dull and uninspired. However, it offers attacking opportunities for some sides, and few lines are quite sharp. Often a trade occurs, and black after gaining a tempo (or unit of time) gains a well placed knight. Pillsbury's game in 1896 against Emmanuel Lasker testifies to this. The Black counterattack in the center also avoids the Ruy Lopez, Giuoco Piano, and other lines of the Italian Game.

If White defends his attacked king pawn with 3. Nc3, Black can obtain equal chances by transposing into the Four Knights Game with 3...Nc6 or by entering the Petrov's Three Knights Game with 3... Bb4.

Another possibility is 3. Bc4 Nxe4 4. Nc3, the Boden-Kieseritzky Gambit. It is not considered wholly sound, since Black has several viable options. He can accept the gambit with 4... Nxc3 5. dxc3 f6, although he must play carefully after 6. 0-0 (for example 6... Bc5?? 7. Nxe5! is disastrous; 6... d6 and 6... Nc6 are good). Another possibility is returning the gambit pawn with 4... Nxc3 5. dxc3 c6 6. Nxe5 d5, which equalizes. A third possibility is transposing to the Italian Four Knights Game with 4... Nc6, and if 5. Nxe4, d5. If 5. Bxf7+?, Kxf7 6. Nxe4 d5 gives Black the bishop pair and control of the center. If 5. 0-0, Black plays 5... Nxc3 6. dxc3 and now Black can play 6... Qe7 7. Ng5 Nd8, as recommended by Fischer in My 60 Memorable Games, or 6... f6 transposing to the main line of the Boden-Kieseritzky.

White usually prefers 3. Nxe5, the Classical Variation, or 3. d4, the Steinitz Variation.

After 3. Nxe5, Black should not continue to copy White's moves and try to restore the material balance immediately with 3... Nxe4? because after 4. Qe2 White will either win material (4... Nf6?? 5. Nc6+ wins Black's queen, and after 4... d5 5. d3 Qe7 6. dxe4 Qxe5 7. exd5 Black loses a pawn), or obtain a superior position (4... Qe7 5. Qxe4 d6 6. d4 f6 7. Nc3 dxe5 8. Nd5 Qd6 9. Bf4 Nd7 10. 0-0-0 and White has a big advantage). Black usually plays 3... d6. White can make a speculative sacrifice by trying the Cochrane Gambit with 4. Nxf7?!. More often, White follows the main line 4. Nf3 Nxe4 5. d4 d5 6.Bd3, where he will try to drive Black's advanced knight from e4 with moves like c4 and Re1. White can instead force simplification with Lasker's 5. Qe2 Qe7 6. d3. This is generally only good enough for a draw, which Black should be satisfied with. Another possibility, explored by Keres, is 5. c4.

Wilhelm Steinitz favored 3. d4. Black can capture either white pawn. After 3... exd4 4. e5 (4. Bc4 transposes into the Bishop's Opening) Ne4 5. Qxd4 d5 6. exd6 Nxd6 7. Nc3 Nc6 8. Qf4 the game is approximately equal. After the other capture, 3... Nxe4, 4. Bd3 d5 (amazingly, 4... Nc6!? 5. Bxe4 d5, intending 6. Bd3 e4, is also possible) 5.Nxe5, either 5... Nd7 or 5... Bd6 gives roughly equal chances.

Karpov, Yusupov, Marshall, Kramnik, and Pillsbury have frequently played the Petrov as Black.

The ECO codes for Petrov's Defence are C43 (for 3. d4 exd4 4. e5 Ne4 5. Qxd4) and C42 for all other lines.