London System
1.d4 d5 2.Bf4 · you play white
4 chapters, 8 moves deep, get you to 92% of what you will actually meet. The other 2 cover the last 6%.
Course progress
0 of 99 decisions
0 still learning · 99 not asked yet
2 more chapters are below the depth for your level, together 6% of what you meet.
Drill this opening
Any chapter or study, asked cold — whether or not you owe it. Nothing here is unlocked by anything else.
At your level
Level
Improving
Depth
16 plies of this opening
Chapters
4
Decisions
99
0/99
How this goes wrong at your level
Counted from 4,500,000 games by players in your band. These are moves that get played often and then lose — no engine was asked for an opinion.
What you are most likely to fall for
1.d4 d5 2.Bf4 Bg4
e3 — played 8% of the time here.
You score 5% after it, against 50% for everything else played from this position, over 81 games.
Instead:
Nd2
58%
Nf3
56%
Nc3
54%
1.d4 d5 2.Bf4 Nf6 3.e3 e6 4.Nf3 c5 5.Nc3 Nc6
Bb5 — played 28% of the time here.
You score 43% after it, against 68% for everything else played from this position, over 108 games.
Instead:
Nb5
73%
What your opponents fall for
1.d4 d5 2.Bf4 e6 3.e3 f5 4.Nf3 Nf6 5.Nc3
Bd6 — played 31% of the time here.
They score 27% after it, against 57% for everything else played from this position, over 49 games.
They should play:
c6
58%
1.d4 d5 2.Bf4 Nf6 3.e3 Bf5 4.Nf3 e6 5.c3 Nc6 6.Qb3
b6 — played 23% of the time here.
They score 12% after it, against 54% for everything else played from this position, over 33 games.
They should play:
Rb8
53%
Found by testing 94,688 decisions in your band’s games and keeping only those where the drop in score is more than four standard errors below the alternatives. About 3.17 of these would be expected by chance alone.
Your moves are chosen by the engine and checked against 3,439,091 games (Lichess Elite (2500+ vs 2300+), 2024-12 → 2025-11); their replies are what people actually play. Evaluations from Stockfish 17.1, our own run at depth 18 (CC0 1.0 Universal), covering 100% of this course.