User:MaxBrowne/sandbox

Nimzo-Indian Defence (3.Nc3 Bb4)
Advocated by Nimzowitsch as early as 1913, the Nimzo-Indian Defence was the first of the Indian systems to gain full acceptance. It remains one of the most popular and well-respected defences to 1.d4, and White often chooses move orders designed to avoid it. Black attacks the centre with pieces and is prepared to trade a bishop for a knight to weaken White's queenside with doubled pawns.

Queen's Indian Defence (3.Nf3 b6)
The Queen's Indian Defence is considered solid, safe, and perhaps somewhat drawish. Black often chooses the Queen's Indian when White avoids the Nimzo-Indian by playing 3.Nf3 instead of 3.Nc3. Black constructs a sound position that makes no positional concessions, although sometimes it is difficult for Black to obtain good winning chances. Karpov is a leading expert in this opening.

Bogo-Indian Defence (3.Nf3 Bb4+)
The Bogo-Indian Defence is a solid alternative to the Queen's Indian, into which it sometimes transposes. It is less popular than that opening, however, perhaps because many players are loath to surrender the (particularly without doubling White's pawns), as Black often ends up doing after 4.Nbd2. The classical 4.Bd2 Qe7 is also often seen, although more recently 4...a5!? and even 4...c5!? have emerged as alternatives. Transposition to the Nimzo-Indian with 4.Nc3 is perfectly playable but rarely seen, since most players who play 3.Nf3 do so in order to avoid that opening.

Blumenfeld Gambit (3.Nf3 c5 4.d5 b5)
The Blumenfeld Gambit (or Countergambit) bears a superficial but misleading resemblance to the Benko Gambit, as Black's goals are very different. Black gambits a wing pawn in an attempt to build a strong centre. White can either accept the gambit or decline it to maintain a small positional advantage. Although the Blumenfeld is playable for Black it is not very popular.

Other lines

 * 1.d4 Nf6 2.c4 e6 3.Nf3 b5 Polish Defence
 * 1.d4 Nf6 2.c4 e6 3.a3?! Australian Attack

Grünfeld Defence (3.Nc3 d5)
Ernst Grünfeld debuted the Grünfeld Defence in 1922. Distinguished by the move 3...d5, Grünfeld intended it as an improvement to the King's Indian which was not considered entirely satisfactory at that time. The Grünfeld has been adopted by World Champions Smyslov, Fischer, and Kasparov.

King's Indian Defence (3.Nc3 Bg7)
The King's Indian Defence is aggressive and somewhat risky, and generally indicates that Black will not be satisfied with a draw. Although it was played occasionally as early as the late 19th century, the King's Indian was considered inferior until the 1940s when it was featured in the games of Bronstein, Boleslavsky, and Reshevsky. Fischer's favoured defence to 1.d4, its popularity faded in the mid-1970s. Kasparov's successes with the defence restored the King's Indian to prominence in the 1980s.

Benoni Defence
The Benoni Defense is a risky attempt by Black to unbalance the position and gain active piece play at the cost of allowing White a pawn wedge at d5 and a central majority. The most common Benoni line is the Modern Benoni (3.d5 e6 4.Nc3). Tal popularised the defence in the 1960s by winning several brilliant games with it, and Bobby Fischer occasionally adopted it, with good results, including a win in his 1972 World Championship match against Boris Spassky. Often Black adopts a slightly different move order, playing 2...e6 before 3...c5 in order to avoid the sharpest lines for White. v

Benko Gambit (or Volga Gambit) (3.d5 b5)
The Benko Gambit is often played by strong players, and is very popular at lower levels. Black plays to open lines on the queenside where White will be subject to considerable pressure. If White accepts the gambit, Black's compensation is positional rather than tactical, and his initiative can last even after many piece exchanges and well into the endgame. White often chooses instead either to decline the gambit pawn or return it.

Old Indian Defence (2...d6 3.Nc3 e5)
The Old Indian Defence was introduced by Tarrasch in 1902, but it is more commonly associated with Chigorin who adopted it five years later. It is similar to the King's Indian in that both feature a ...d6 and ...e5 pawn centre, but in the Old Indian Black's king bishop is developed to e7 rather than being fianchettoed on g7. The Old Indian is solid, but Black's position is usually cramped and it lacks the dynamic possibilities found in the King's Indian.

Budapest Gambit (2... e5)
The Budapest Gambit is rarely played in grandmaster games, but more often adopted by amateurs. Although it is a gambit, White cannot hold on to his extra pawn without making compromises in the deployment of his pieces, so he often chooses to return the pawn and retain the initiative.

Other lines
The Accelerated Queen's Indian Defence (2...b6) is playable, although modern theory favours the Queen's Indian only after 2...e6 3 Nf3.
 * 1.d4 Nf6 2.c4 b6 Accelerated Queen's Indian Defence

The Slav Indian Defence is an obscure idea that may transpose into the King's Indian or Slav Defence.
 * 1.d4 Nf6 2.c4 c6 Slav Indian Defence

The Black Knights' Tango or Mexican Defence introduced by Carlos Torre in 1925 in Baden-Baden shares similarities with Alekhine's Defence as Black attempts to induce a premature advance of the white pawns. It may transpose into many other defences.
 * 1.d4 Nf6 2.c4 c6 3.Nf3 b5 Kudischewitsch gambit
 * 1.d4 Nf6 2.c4 Nc6 Black Knights' Tango

The Döry Defence (2...Ne4 or 2...e6 3.Nf3 Ne4) is uncommon, but it was sometimes adopted by Keres. It will sometimes transpose into a variation of the Queen's Indian Defence but there are also independent lines.
 * 1.d4 Nf6 2.c4 d6 3.Nc3 Bf5 Janowski Indian Defence
 * 1.d4 Nf6 2.c4 Ne4 Döry Defence

1.d4 Nf6 side lines

 * 1.d4 Nf6 2.Nf3 h6 3.c4 g5 Nadanian Attack

The Nadanian Attack (1.d4 Nf6 2.Nf3 h6 3.c4 g5) is an aggressive attempt by Black to unbalance the position. The early 2...h6 and 3...g5 are designed to deal with a drawish variations such as Colle System, London System and Torre Attack. The line was introduced in 2005 by Ashot Nadanian, but has never enjoyed widespread popularity among top-flight chess players.

The Neo-Indian Attack, Torre Attack, and Trompowsky Attack are White anti-Indian variations. Related to the Richter-Veresov Attack, they feature an early Bg5 by White and avoid much of the detailed theory of other queen's pawn openings.
 * 1.d4 Nf6 2.c4 e6 3.Bg5 Neo-Indian Attack
 * 1.d4 Nf6 2.Bg5 Trompowsky Attack
 * 1.d4 Nf6 2.Nf3 e6 3.Bg5 Torre Attack

Another option is the Barry Attack, popular with club players and characterised by the moves 1.d4 Nf6 2.Nf3 g6 3.Nc3 d5 4.Bf4 Bg7 5.e3 0-0 6.Be2. White usually follows up with Ne5 and h2–h4–h5, a direct attack on the black king. The Barry Attack has also been tried out at Grandmaster level by Mark Hebden and Julian Hodgson.
 * 1.d4 Nf6 2.Nf3 g6 East Indian Defence
 * 1.d4 Nf6 2.Nf3 g6 3.Nc3 d5 4.Bf4 Bg7 5.e3 0-0 6.Be2 Barry Attack