Main line against ...d5 is variation 1 of 6 in the London System course, a beginner opening course for White (ECO D02). It runs 15 moves and begins 1. d4 d5 2. Bf4 Nf6 3. e3 e6 4. Nf3 c5 …. Black mirrors with ...d5 and ...e6. White completes the standard setup and keeps an easy, safe position. 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 an equal share of the centre and stops White playing e4 easily.
2. Bf4 – The key London move: the bishop leaves before e3 shuts it in, and it controls e5.
2... Nf6 – Black develops toward the centre and prepares to castle.
3. e3 – Now e3 is the right move: it supports d4 and opens the way for the light-squared bishop.
3... e6 – Black frees the dark-squared bishop and prepares ...c5.
4. Nf3 – Develops a piece, controls e5 and gets ready to castle.
4... c5 – The most active plan for Black: hitting White's d4 pawn from the side.
5. c3 – Completes the pyramid. If Black takes on d4, White recaptures with a pawn and keeps a strong centre.
5... Nc6 – Adds a third attacker to d4.
6. Nbd2 – The knight goes to d2, not c3, so it doesn't block the c-pawn and can support e4 later.
6... Bd6 – Black challenges White's strong bishop on f4.
7. Bg3 – Keeps the bishop. If Black takes on g3, White recaptures toward the centre with hxg3 and gets a half-open h-file.
7... O-O – Black castles to safety.
8. Bd3 – The bishop points at h7, the usual target for White's kingside play.
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