London System
The London System set-up
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| Moves | d4, Nf3, Bf4, e3, Bd3, Nbd2, c3 | ||||||||||||||||||||||||||||||||||||||||||||
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| ECO | D02, A46, A48 | ||||||||||||||||||||||||||||||||||||||||||||
| Origin | James Mason | ||||||||||||||||||||||||||||||||||||||||||||
| Named after | 1922 London tournament | ||||||||||||||||||||||||||||||||||||||||||||
| Parent | Queen's Pawn Game | ||||||||||||||||||||||||||||||||||||||||||||
The London System is an opening system in chess characterized by the moves (with any first move by Black):
In addition to these moves, in the standard system, White supports the d pawn and bishop with a pawn on e3, the other bishop is developed to d3, the knights are developed to f3 and d2, and the d pawn is reinforced again by c3. However, some variation exists; for example, Nc3 can be played instead of c3, entering the Rapport–Jobava System (or Jobava London).
The system can be used against virtually any Black response (although most popular against 1...d5) and thus comprises a smaller body of opening theory than many other openings. Black's most common response to the system involves playing c5 and Qb6 (pressuring White's now undefended pawn). White also has great flexibility in move order (2.Nf3 and then 3.Bf4 is common), and the system has many transpositional opportunities. For example, White can transpose to the Queen's Gambit with c4 (instead of c3 or Nc3), and Black can transpose to the Caro–Kann Defence with ...cxd4 exd4.
White's set-up often results in a closed game, and often involves a plan to put a knight on e5, supported by the pawn and bishop. Although it has a reputation as a solid opening, the London System has been criticized for resulting in repetitive games and a lack of dynamic play. White can instead adopt a more flexible and theoretical approach after 2.Bf4, rather than committing to the same initial moves regardless of Black's response, often resulting in a more dynamic game.
In the Encyclopaedia of Chess Openings, the opening is not assigned its own unique codes, but it appears in lines within A46 (against 1...Nf6 without g6), A48 (against 1...Nf6 with g6), and D02 (against 1...d5). The opening was employed by Ding Liren in the sixth game of the World Chess Championship 2023 against Ian Nepomniachtchi, resulting in a win for Ding.