Indian Defense: London System

About this variation

The London System against 1...Nf6, reached with 2. Nf3 and 3. Bf4 or 2. Bf4 directly. Black often chooses a King's Indian set-up with ...g6.

This is the London System against 1...Nf6, reached by 1. d4 Nf6 2. Bf4 or 2. Nf3 and 3. Bf4. Because Black has delayed ...d5, the position is more flexible, and Black can choose a King's Indian or Grünfeld style set-up with ...g6 and ...Bg7, or a Queen's Indian style set-up with ...b6 and ...Bb7, as well as the classical ...d5.

Against the King's Indian set-up, White usually keeps the pyramid of pawns on c3, d4 and e3 and plays h3 to give the bishop a retreat. Black aims for ...d6 and ...e5, and the main fight is whether White can keep the bishop on f4 active or whether Black's central break pushes it back. An early h4-h5 attack is also possible against Black's fianchettoed king.

Against ...b6 and ...Bb7, White often plays h3, Bd3, O-O and a later e4, because the bishop on b7 makes ...d5 less natural for Black. Against ...d5 the game transposes to the standard London. In all cases White's structure is sound and the plans are easy to learn, which is why the London is so popular with club players, while strong players like Magnus Carlsen also use it as a surprise weapon.

The main lesson for both sides is that move orders matter. White should choose between the Accelerated move order and Nf3 first depending on which Black set-ups worry them most, and Black should pick a line that makes the bishop on f4 uncomfortable.

For Black, one effective approach is to aim for ...c5 and ...Qb6 early, which transposes to the Poisoned Pawn ideas and forces White to make a concession on the queenside. Another is a quick ...d6 and ...e5, which challenges the bishop and gains central space before White's pyramid is complete.

It is one of the main lines of the London System.