Chess Opening Theory/1. d4/1...d5/2. Nf3/2...Nf6/3. Bf4

London System with ...d5 and ...Nf6

The London System is a Queen's pawn opening where White develops their dark squared bishop to f4 in order to provide additional flexibility in what will become a closed position. After Black develops to d5 and Nf6, White plans to place their King's knight on f3 and pawns on e3 and c3 to strengthen their centre. It can be used against nearly all of Black's common responses to 1. d4, including 1...d5. From this position, Black usually plays either 3...c5, 3...e6, 3...Bf5, 3...c6, 3...g6, or 3...Nc6.

References

• Chess Opening Crash Course: The London System
• Win with the London System. 2005. Sverre Johnsen, Vlatko Kovačević. ISBN 1-9046-0035-2.