London System
ECO D02, A48 · 1. d4 d5 2. Nf3 Nf6 3. Bf4
The London System is a setup for White based on d4, Bf4, e3, Nf3, c3 and Bd3, usually with Nbd2 and castling. It can be played against almost any Black defense, which makes it extremely popular at club level and online, and it has also been used by Magnus Carlsen.
Plans for White
White develops the dark-squared bishop to f4 before playing e3, keeps a solid pawn triangle and castles. Plans include a kingside attack with Ne5, Qf3 and h4, the h3 and g4 expansion, or a central break with c4 or e4.
Plans for Black
Black challenges with ...c5 and ...Qb6, hitting b2, or with ...Bd6 to trade the dark-squared bishop. King's Indian setups with ...g6, ...d6 and ...e5 aim at the f4 bishop.
Typical pawn structures
A solid d4-e3-c3 triangle with the bishop outside the chain.
Who it suits
Players who want a reliable system with little theory.
Common traps
Against ...c5 and ...Qb6 White must watch b2; Black must watch Bxh7+ and Ne5 attacks.
Variations
- London System, with Bd3 — 1. d4 Nf6 2. Nf3 g6 3. Bf4 Bg7 4. e3 d6 5. Bd3
- London System, with Be2 — 1. d4 Nf6 2. Nf3 g6 3. Bf4 Bg7 4. e3 d6 5. Be2
- London System: Poisoned Pawn Variation — 1. d4 Nf6 2. Nf3 d5 3. Bf4 c5 4. e3 Qb6 5. Nc3