Nimzo-Larsen Attack

The Nimzo-Larsen Attack, also called the Nimzowitsch–Larsen Attack, Larsen's Opening or the Queen's Fianchetto Opening, starts with 1. b3. The move clears b2 for the queen's bishop, which then works along the long diagonal against the central squares and Black's kingside rather than claiming the center with pawns. Black is free to build a classical center, and White aims to undermine it later. Independent lines carry the code A01; the opening is frequently reached by transposition, notably via 1. Nf3 d5 2. b3, an order that rules out 1...e5. Engines rate the starting position as balanced.

The Modern Variation, 1...e5, is the most frequent reply. White can let Black set up pawns on e5 and d5 and then hit them, as in 1. b3 e5 2. Bb2 Nc6 3. e3 d5 4. Bb5 Bd6 5. f4, where the pin of the c6-knight and the pressure on g7 and h8 make the e5-pawn awkward to maintain. Alternatively, 1. b3 e5 2. Bb2 Nc6 3. c4 fights for d5 in reversed-Sicilian fashion, and Black may answer in Open Sicilian style with 3...Nf6 4. e3 d5 5. cxd5 Nxd5 or in Closed Sicilian style with 3...g6. The Pachman Gambit, 1. b3 e5 2. Bb2 Nc6 3. f4, is a sharper option.

After 1...d5, the Classical Variation, White can stop ...e5 and steer toward a reversed Nimzo-Indian with an extra tempo: 1. b3 d5 2. Bb2 c5 3. e3 Nc6 4. Nf3 Nf6 5. Bb5. Against a London-style setup with ...Bf5, White may adopt a double fianchetto and push e4, for example 1. b3 d5 2. Bb2 Bf5 3. d3 e6 4. Nd2 Nf6 5. g3 Be7 6. Bg2 h6 7. e4 Bh7. The Graz Attack, 1. b3 d5 2. Ba3, is a rare deviation. In the Indian Variation, 1. b3 Nf6 2. Bb2 g6, White can reply 3. e4, since 3...Nxe4 drops the rook to 4. Bxh8; 3. g4 is the Spike Variation. The English Variation, 1...c5, is mainly transpositional, with 2. e4 giving a Sicilian and 2. c4 a Symmetrical English. Rarer tries include 1...b6, 1...f5 and 1...b5.

John Owen used the opening in the 1870s, in effect playing his own defense with an extra move. Aron Nimzowitsch experimented with 1. b3 in the 1920s and 1930s but usually began with 1. Nf3. Bent Larsen adopted it often between 1968 and 1972, though he lost a 17-move game with it to Boris Spassky in the 1970 USSR versus Rest of the World match; Bobby Fischer also played it five times in 1970. Vladimir Bagirov used it for decades, and Pavel Blatny, Artashes Minasian and Baadur Jobava are among later specialists. Its main lines are considered equal, but Black often meets unfamiliar structures, which helps explain its use as a surprise in elite online blitz by Hikaru Nakamura and Magnus Carlsen.