London System: ...c5, ...Qb6 and ...c4 is variation 1 of 5 in the Beating 1.d4 Sidelines course, a intermediate opening course for Black (ECO D02). It runs 22 moves and begins 1. d4 d5 2. Bf4 c5 3. e3 Nc6 4. c3 Qb6 …. Black hits d4 and b2 at once. After Qb3 c4 Qc2 the white queen is pushed back, Black develops the bishop to f5 with tempo and later expands on the queenside. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. d4 – White takes the centre and frees the c1 bishop.
1... d5 – Black claims an equal share of the centre and stops e4.
2. Bf4 – The London bishop leaves before e3 so it is not shut in, and it watches e5 and c7.
2... c5 – The most testing answer: Black attacks d4 straight away, before White has built the c3 support.
3. e3 – Supports d4 and opens the f1 bishop. White keeps the London pyramid in mind.
3... Nc6 – Adds a second attacker to d4 and prepares ...Qb6 to hit b2 and d4 together.
4. c3 – Completes the pyramid so that d4 is defended by a pawn.
4... Qb6 – The point of Black's set-up: the queen hits b2, which the bishop on c1 used to defend, and adds pressure on d4.
5. Qb3 – White defends b2 and offers a queen trade, which would give him the half-open a-file after ...Qxb3 axb3.
5... c4 – Black avoids the trade with tempo: the white queen is attacked and Black gains space on the queenside.
6. Qc2 – The queen keeps an eye on b2 and the light squares f5 and h7.
6... Bf5 – Develops the light-squared bishop outside the pawn chain and attacks the queen again, before ...e6 locks it in.
7. Qc1 – The only good square: the queen still guards b2 and stays away from Black's minor pieces.
7... e6 – Now that the bishop is out, ...e6 frees the f8 bishop and supports d5.
8. Nd2 – The b1 knight goes to d2, where it supports a later e4 and does not block the c-pawn; the g1 knight comes to f3 next.
8... Nf6 – Develops toward the centre, controls e4 and prepares castling.
The lesson goes on for 6 more moves, each with its explanation.
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