|Moves||1.d4 Nf6 2.c4 e6 3.Nf3 b6|
The Queen's Indian Defense (QID) is a chess opening defined by the moves:
The opening is a solid defense to the Queen's Pawn Game. 3...b6 increases Black's control over the central light squares e4 and d5 by preparing to fianchetto the queen's bishop, with the opening deriving its name from this maneuver. As in the other Indian defenses, Black attempts to control the center with pieces, instead of occupying it with pawns in classical style.
By playing 3.Nf3, White sidesteps the Nimzo-Indian Defense that arises after 3.Nc3 Bb4. The Queen's Indian is regarded as the sister opening of the Nimzo-Indian, since both openings aim to impede White's efforts to gain full control of the center by playing e2-e4. Together, they form one of Black's most well-respected responses to 1.d4.
4. g3 (E15-E19) has long been White's most popular line against the Queen's Indian. It contests the long diagonal by preparing to fianchetto the light-squared bishop. The standard response for Black through the 1970s was 4...Bb7, but 4...Ba6 has since become the topical line. A rarer third option is 4...Bb4+, which aims to exchange the less useful dark-squared bishop, though this line tends to leave Black with a slightly passive position.
White can defend the pawn at c4 with a piece by playing 5.Nbd2, 5.Qa4, 5.Qc2 or 5.Qb3, but these moves all diminish control of d4, making ...c7-c5 an effective reply for Black; therefore 5. b3 is White's most common response. However, it weakens the dark squares slightly, which Black can take advantage of by playing 5...Bb4+. Now 6.Nbd2? loses material after 6...Bc3 7.Rb1 Bb7 threatening 8...Be4, an opening trap which has ensnared players such as Kamran Shirazi. White's best move is therefore 6. Bd2. However, after 6...Be7 7. Bg2 c6 Black is ready to play ...d7-d5, again attacking the c-pawn. If White plays cxd5 then ...cxd5 is considered to equalize for Black. Thus White usually plays 8. Bc3 to clear this square, and the main line continues 8...d5 9. Ne5 Nfd7 10. Nxd7 Nxd7 11. Nd2 0-0 12. 0-0 to maintain central tension. The effect of Black's check has been to lure White's bishop to c3 where it blocks the c-file. This, the current main line of the Queen's Indian, is considered equal by theory and became a frequent guest in grandmaster praxis in the 1980s.
After 5. b3, Black also has several playable alternatives to 5...Bb4+, the most common of which is 5...Bb7 6. Bg2 Bb4+ 7. Bd2 a5. When White plays Nc3, Black will exchange bishop for knight in order to enhance his control over the central light squares, and play on the queenside with moves such as ...a5-a4 and ...b5. Other possibilities for Black include 5...d5 and 5...b5.
More recently, several grandmasters, including Alexander Beliavsky, Ni Hua, Veselin Topalov, and Magnus Carlsen, have played 5. Qc2. The idea is to allow Black's counterthrust ...c5, the main line running 5...Bb7 6. Bg2 c5. The fashion is for White to sacrifice a pawn with 7. d5, gaining active play. This idea has scored well for White, and new ideas have been cropping up since 2008. The 5.Qc2 lines had previously scored poorly for White according to Emms.
The classical main line of the Queen's Indian, the most frequently played line from the 1950s until 4....Ba6 became popular in the 1980s, usually continues: 5. Bg2 Be7 6. 0-0 0-0 7. Nc3 Ne4 8. Qc2 Nxc3 9. Qxc3. White has a spatial advantage, but Black has no weaknesses and can choose from a variety of ways to create counterplay, such as 9...c5, 9...f5 or 9...Be4. These lines are well known for their drawish tendencies and 4...Bb7 is nowadays often employed by Black as a drawing weapon. White has tried various deviations from the main line in an attempt to unbalance the play. These include:
The Petrosian Variation, prepares 5.Nc3 without being harassed by ...Bb4 pinning the knight. See Gurevich (1992) for an extensive analysis. This variation was often used by Garry Kasparov early in his career.
Black can choose between 4...Bb7 and 4...Bb4.
After 4.Nc3 Bb7 5.Bg5 Be7, White can play 6.e3 or 6.Qc2.
4. Nc3 Bb4 is a Queen's Indian / Nimzo-Indian line (also 3.Nc3 Bb4 4.Nf3 b6). Moves for White include 5.Bg5, 5.e3, and 5.Qb3. After 5.Bg5, Black may play 5...Bb7 or 5...h6. 4. Nc3 Bb4 5.e3 is a Nimzo-Indian / Queen's Indian line. With move 5.e3, Black usually plays 5...Bb7. After 5.Qb3, Black usually plays 5...c5.
The position after 5. Bg5 h6 6. Bh4 g5 7. Bg3 Ne4 8. Qc2 was heavily played and analysed in the 1980s.
Preparing to develop the king's bishop and castle kingside, was also a favorite of Tigran Petrosian. This apparently quiet development may lead to complex middlegame play. Black usually replies 4...Bb7, then play may continue 5.Bd3 d5 6.O-O or 5.Nc3 Bb4, transposing into the Nimzo-Indian Defence.
The Miles Variation, which simply develops the bishop to a good square; despite some success by its originator, this idea has never been popular.
The Encyclopaedia of Chess Openings classifies the Queen's Indian under codes E12 to E19 according to the following scheme: