Against an early ...c5 is variation 3 of 6 in the London System course, a beginner opening course for White (ECO D02). It runs 24 moves and begins 1. d4 d5 2. Bf4 c5 3. e3 Nc6 4. Nf3 Nf6 …. Black hits d4 at once with 2...c5. White develops calmly with e3, Nf3 and Nbd2, recaptures exd4, then uses the Qb3 and Nh4 ideas to bother Black's light-squared bishop. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. d4 – Takes the centre and opens a path for the dark-squared bishop.
1... d5 – Black claims the centre.
2. Bf4 – The London bishop comes out before e3.
2... c5 – Black challenges d4 immediately, hoping to exploit that the c1 bishop has left the queenside and b2 is less protected.
3. e3 – Supports d4 and opens the f1 bishop. If ...cxd4, White recaptures exd4 with a solid centre.
3... Nc6 – Develops and adds pressure to d4.
4. Nf3 – Develops, guards d4 and controls e5.
4... Nf6 – Black develops and covers d5 and e4.
5. Nbd2 – Keeps the c-pawn free to go to c3 and supports a later Ne5 or e4.
5... cxd4 – Black releases the tension so that the light-squared bishop can come to f5 with a clear target.
6. exd4 – Recapturing with the pawn keeps a pawn on d4 and opens the e-file for White's rook.
6... Bf5 – The bishop takes the active b1-h7 diagonal before ...e6 shuts it in.
7. c3 – Supports d4 and gives the queen the b3 square to attack b7.
7... e6 – Black frees the f8 bishop and supports d5.
8. Qb3 – Attacks b7 now that the c8 bishop has left. Black must spend a move defending it.
8... Qc8 – Defends b7 while keeping the queen flexible on the c-file.
The lesson goes on for 8 more moves, each with its explanation.
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