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| Moves | 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| ECO | C55–C59 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Origin | late 16th century | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Parent | Italian Game | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Chessgames.com opening explorer | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The Two Knights Defense is a chess opening that begins with the moves:
First recorded by Polerio[1] (c.1550–c.1610) in the late 16th century, this line of the Italian Game was extensively developed in the 19th century. Black's third move is a more aggressive defense than the Giuoco Piano which would result from 3...Bc5. In fact, Bronstein suggested that the term "defense" does not fit, and that the name "Chigorin Counterattack" would be more appropriate.[2] The Two Knights has been adopted as Black by many aggressive players including Chigorin and Keres, and World Champions Tal and Boris Spassky. The theory of this opening has been explored extensively in correspondence chess by players such as Berliner and Estrin.
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| This article uses algebraic notation to describe chess moves. |
| a | b | c | d | e | f | g | h | ||
| 8 | 8 | ||||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h |
| a | b | c | d | e | f | g | h | ||
| 8 | 8 | ||||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h |
| a | b | c | d | e | f | g | h | ||
| 8 | 8 | ||||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h |
White must respond to the attack on his e-pawn (For explanation of notation, see Chess Opening Theory Table).
| 4 | 5 | 6 | 7 | 8 | 9 | 10 | |||
|---|---|---|---|---|---|---|---|---|---|
| Wilkes-Barre or Traxler Variation | Ng5 Bc5!? |
Bxf7+! Ke7 |
Bb3! - |
- - |
- - |
- - |
- - |
||
| Lolli Variation | ... d5 |
exd5 Nxd5?! |
d4! - |
- - |
- - |
- - |
- - |
||
| Fried Liver Attack | ... ... |
... ... |
Nxf7!? Kxf7 |
Qf3+ Ke6 |
Nc3 Nb4 |
a3! Nxc2+ |
Kd1 Nxa1 |
- - |
|
| Morphy Variation | ... d5 |
exd5 Na5 |
d3 h6 |
Nf3 e4 |
Qe2 Nxc4 |
dxc4 Bc5 |
- - |
||
| Main Line | ... ... |
... ... |
Bb5+ c6 |
dxc6 bxc6 |
Be2 h6 |
Nf3 e4 |
Ne5 - |
||
| Steinitz Variation | ... ... |
... ... |
... ... |
... ... |
... ... |
Nh3 - |
- - |
||
| Ulvestad Variation | ... ... |
... b5 |
Bf1! Nd4 |
c3 Nxd5 |
Ne4 - |
- - |
- - |
||
| Fritz Variation | ... ... |
... Nd4 |
c3 b5 |
Bf1! Nxd5 |
Ne4 - |
- - |
- - |
||
| Boden-Kieseritzky Gambit | Nc3 Nxe4 |
O-O Nxc3 |
dxc3 Qe7 |
Ng5 Nd8 |
- - |
- - |
- - |
||
| Giuoco Pianissimo, by transposition | d3 Bc5 |
- - |
- - |
- - |
- - |
- - |
- - |
||
| 3 | ... d5!? |
exd5 Nxd5 |
- - |
- - |
- - |
- - |
- - |
||
| 4 | ... Be7 |
- - |
- - |
- - |
- - |
- - |
- - |
||
| 5 | d4 exd4 |
- - |
- - |
- - |
- - |
- - |
- - |
||
| 6 | ... ... |
O-O Nxe4 |
Re1 d5 |
Bxd5 Qxd5 |
Nc3 - |
- - |
- - |
||
| Max Lange Attack | ... ... |
... Bc5 |
e5 d5 |
exf6 dxc4 |
Re1+ Be6 |
Ng5 Qd5 |
Nc3 Qf5 |
||
| 8 | ... ... |
e5 d5 |
Bb5 Ne4 |
Nxd4 Bc5 |
- - |
- - |
- - |
||
| 9 | ... ... |
... Ne4 |
- - |
- - |
- - |
- - |
- - |
||
| 10 | ... ... |
... Ng4 |
- - |
- - |
- - |
- - |
- - |
Siegbert Tarrasch called 4.Ng5 a "duffer's move" (ein richtiger Stümperzug) and Panov called it "primitive", but this attack on f7 practically wins a pawn by force. Despite Tarrasch's criticism, many players consider 4.Ng5 White's best chance for an advantage and it has been played by World Champions Wilhelm Steinitz, Bobby Fischer, Anatoly Karpov, Garry Kasparov, and Viswanathan Anand.
Czech problemist Karel Traxler played 4...Bc5!? in Reinisch–Traxler, Prague 1896. Some decades later, several Pennsylvania chess amateurs, (mainly K. Williams) analyzed the variation and decided to name it after their hometown Wilkes-Barre, Pennsylvania, so today 4...Bc5 is known as both the Traxler Variation and (in the U.S.A. and the United Kingdom[3] only) the Wilkes-Barre Variation. This bold move ignores White's attack on f7 and leads to wild play where a number of long variations have been analyzed to a draw by perpetual check. White can play 5.d4, 5.Nxf7, or 5.Bxf7+. After 5.d4 d5!, White's best is to go into an equal endgame after 6.dxc5 dxc4 7.Qxd8+. Other sixth moves have scored very badly for White. The usual move used to be 5.Nxf7, but this is very complicated after 5...Bxf2+. The current main lines all are thought to lead to drawn or equal positions, e.g. after 6.Kxf2 Nxe4+ 7.Kg1, or even 7.Ke3. In the year 2000, this last move (which was already considered by Traxler himself) was credited as the 'refutation' of the Traxler variation, after an article in the New in Chess Yearbook series, featuring a cover diagram after White's seventh move. However, computer analysis subsequently showed that Black can probably force a draw after this move as well. White's best try for an advantage is probably 5.Bxf7+ Ke7 6.Bb3, as this poses Black the most problems. No grandmasters have regularly adopted the Wilkes-Barre as Black, but Alexander Beliavsky and Alexei Shirov have played it occasionally even in top competition. No clear refutation is known.
More common is 4...d5 5.exd5. The recapture 5...Nxd5?! is very risky. Pinkus tried to bolster this move with analysis in 1943 and 1944 issues of Chess Review, but White gets a strong attack with either the safe Lolli Variation 6.d4! or the sacrificial Fried Liver (or Fegatello) Attack 6.Nxf7!? Kxf7 7.Qf3+ Ke6 8.Nc3. These variations are usually considered too difficult for Black to defend over the board, but they are sometimes used in correspondence play. Instead Black usually chooses to make the opening a gambit by playing 5...Na5 (main line), 5...Nd4 or 5...b5.
After 5...Na5, Morphy would play to hold the gambit pawn with 6.d3. The Morphy Variation has not been popular, since it has long been known that Black obtains good chances for the pawn with 6...h6 7.Nf3 e4 8.Qe2 Nxc4 9.dxc4 Bc5. (Bronstein once tried the piece sacrifice 8.dxe4!? with success, but its soundness is doubtful.[2][4]) Instead, White usually plays 6.Bb5+, when play almost always continues 6...c6 7.dxc6 bxc6 8.Be2 h6. (The move 8.Qf3?!, popular in the nineteenth century and revived by Bogoljubov in the twentieth, is still played occasionally, but Black obtains a strong attack after either 8...h6! or 8...Rb8.) White then has a choice of retreats for the knight. The usual move here is 9.Nf3, after which Black obtains some initiative after 9...e4 10.Ne5 Bd6 (this is considered to be the main line of the Two Knights Defense). Steinitz favored 9.Nh3 instead, although it did not bring him success in his famous 1891 cable match against Chigorin. The Steinitz Variation was mostly forgotten until Fischer revived it in the 1960s. Nigel Short led a second revival of 9.Nh3 in the 1990s, and today it is thought to be about equal in strength to the more common 9.Nf3.
Black's alternatives to 5...Na5, the Fritz Variation 5...Nd4, and Ulvestad's Variation 5...b5, are related as they share a common subvariation. American master Olav Ulvestad introduced 5...b5 in a 1941 article in Chess Review. White has only one good reply. Weak are 6.Bxb5 Qxd5 7.Bxc6 Qxc6 and 6.dxc6 bxc4 7.Nc3; the strongest move is considered the surprising 6.Bf1!, protecting g2 so White can answer 6...Qxd5? with 7.Nc3. 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. German master Alexander Fritz (1857–1932) suggested 5...Nd4 to Carl Schlechter, who wrote about the idea in a 1904 issue of Deutsche Schachzeitung. In 1907 Fritz himself wrote an article about his move in the Swedish journal Tidskrift för Schack. White's best reply is 6.c3, when the game often continues 6...b5 7.Bf1 Nxd5 8.Ne4 or 8.h4.
The attempt to defend the pawn with 4.Nc3 does not work well since Black can take the pawn anyway and use a fork trick to regain the piece, 4.Nc3?! Nxe4! 5.Nxe4 d5. The try 5.Bxf7+? does not help, as Black has the bishop pair and a better position after 5...Kxf7 6.Nxe4 d5. Instead, 4.Nc3 is usually played with the intent to gambit the e-pawn with the Boden-Kieseritzky Gambit, 4.Nc3 Nxe4 5.0-0. This gambit is not commonly seen in tournament play as it is not well regarded by opening theory, but it can offer White good practical chances, especially in blitz chess.
The quiet move 4.d3 transposes into the Giuoco Pianissimo if Black responds 4...Bc5, but there are also independent variations after 4...Be7 or 4...h6. White tries to avoid the tactical battles that are common in other lines of the Two Knights and to enter a more positional game. The resulting positions take on some characteristics of the Ruy Lopez if White plays c3 and retreats the bishop to c2 via Bc4-b3-c2. This move became popular in the 1980s and has been used by John Nunn and others. Black can confound White's attempt to avoid tactical play with 4...d5!?. This move is rarely played as opening theory does not approve, but Jan Piński suggests that it is better than is commonly believed.
White can choose to develop rapidly with 4.d4 exd4 5.0-0. Now Black can equalize simply by eliminating White's last center pawn with 5...Nxe4, after which White regains the material with 6.Re1 d5 7.Bxd5 Qxd5 8.Nc3 but Black has a comfortable position after 8...Qa5 or 8...Qh5, or obtain good chances with the complex Max Lange Attack after 5...Bc5 6.e5 d5. The extensively analyzed Max Lange can also arise from the Giuoco Piano or Scotch Game. White can choose to avoid these lines by playing 5.e5, a line often adopted by Sveshnikov. After 5.e5, either 5...Ne4 or 5...Ng4 is a playable reply, but most common and natural is 5...d5 6.Bb5 Ne4 7.Nxd4 Bc5, with sharp play.