Anglo-Indian Defense

The Anglo-Indian Defense, 1. c4 Nf6 (ECO A15), develops a knight towards the center, watches e4 and d5, and puts off any pawn commitment. The point is to let White's next moves decide the course of the game. If White plays d4, either at once or later, the position usually becomes an Indian Defense such as the Nimzo-Indian, King's Indian or Grünfeld. If White keeps the d-pawn back, Black can still choose between ...c5, heading for Symmetrical English structures, and ...e5, heading for a Reversed Sicilian.

The most common reply by a wide margin is 2. Nc3, the Queen's Knight Variation, which supports e4 and makes d4 less urgent. Against 2...e6, the Hedgehog System, White can play 3. e4, the aggressive Mikenas-Carls Variation. Its main line, the Flohr Variation, runs 3...d5 4. e5 and usually continues 4...d4 5. exf6 dxc3 6. bxc3 Qxf6. Black can instead choose the Kevitz Variation with 3...Nc6 or aim for Sicilian structures with 3...c5. The quieter 2. Nc3 e6 3. Nf3 Bb4 is the Nimzo-English. After 2. Nc3 d5 3. cxd5 Nxd5 4. Nf3, the Anglo-Grünfeld Variation reaches Grünfeld-type play without a white pawn on d4. The sequence 2. Nc3 g6 3. Nf3 Bg7 4. e4, the Anti-Anti-Grünfeld, takes ...d5 out of the position.

The next most common reply is 2. Nf3, the King's Knight Variation. It keeps d4 in reserve and gives Black a choice of named setups. These include the King's Indian Formation (2...g6), which turns into the Grünfeld Formation after 3. g3 d5, as well as the Queen's Indian Formation (2...b6), the Old Indian Formation (2...d6) and the Scandinavian Defense (2...d5). White can also fianchetto with 2. g3, a frequent choice. The direct 2. d4, played less often, transposes to the Indian Defense: Normal Variation and gives up the English move-order finesse.

Fringe tries such as 2. e4 (the Achilles-Omega Gambit), 2. b4 and 2. f4 are rare, and they score worse for White than the main moves. In general the Anglo-Indian is a transpositional opening. How much theory it involves depends on which Indian, Symmetrical or Reversed Sicilian structure the players settle into. Most lines lead to maneuvering play, while the Mikenas-Carls branch is sharper. It ranks among the more frequently reached named positions. The engine considers it roughly balanced, and White scores slightly better than Black in practice.