London System: Poisoned Pawn Variation
The Poisoned Pawn Variation of the London is 3...c5 4.e3 Qb6 5.Nc3, where White leaves b2 unprotected. Black can grab b2, but Nb5 and Rb1 bring dangerous threats, so the engine prefers ...a6 or ...c4 instead.
- Moves
- 1.d4 Nf6 2.Nf3 d5 3.Bf4 c5 4.e3 Qb6 5.Nc3
- ECO
- D02
- Engine
- +0.06 · level (Stockfish 17.1, depth 20)
- Played
- 55 games in our lichess sample
- White scores
- 52.7%
Key ideas for both sides
White
- If Black takes on b2, play Nb5 with the threat of Nc7+ forking the king and a8 rook.
- Rb1 chases the queen from b2 and opens the b-file for an attack.
- Against ...a6, take on c5 and play Bd3 and e4, as in the top engine line.
- Against ...c4, push e4 and e5 to gain space while the queen hunts pawns.
Black
- 5...a6 stops Nb5 and keeps b2 under pressure.
- 5...c4 gains queenside space and prepares a later ...Qxb2, as in the second engine line.
- Before taking on b2, make sure Nb5 and Nc7+ are covered.
- Develop ...Nc6 and ...Bf5 to support the queen and the d5 pawn.
Plans and pawn structure
White gives b2 for development and attacking chances against c7 and the a8 rook. If Black declines with ...a6, White trades on c5 and plays Bd3 and e4 to open the center. After ...c4, White pushes e4 and e5, and Black can win b2 later but must watch the queen. The position gets sharp very quickly.
What the engine plays from here
Stockfish 17.1 at depth 20 rates the position +0.06: level. Its three top choices for Black:
- +0.06 5...a6 6.dxc5 Qxc5 7.Bd3 g6 8.e4
- +0.24 5...c4 6.e4 e6 7.e5 Qxb2 8.Bd2
- +0.41 5...Bd7 6.dxc5 Qxc5 7.Nd4 e6 8.Ncb5
Pawns, from White's side.
How it scores on lichess
55 rated lichess games reached this position; White scored 52.7%.
Light: White wins. Grey: draws. Dark: Black wins. About the sample.
How to play against it
As Black, play 5...a6 before thinking about ...Qxb2, so Nb5 is not possible. If you do take on b2, check Nb5 and Rb1 first. Keep the queen supported by minor pieces.
Questions
What are the moves of the London System: Poisoned Pawn Variation?
The London System: Poisoned Pawn Variation starts 1.d4 Nf6 2.Nf3 d5 3.Bf4 c5 4.e3 Qb6 5.Nc3. Its ECO code is D02.
Is the London System: Poisoned Pawn Variation good for White?
Stockfish 17.1 rates the position +0.06 at depth 20, which is level. A sharp choice for White players who like tactics, but Black can stay safe with ...a6.
What is the main idea of the London System: Poisoned Pawn Variation?
White offers the b2 pawn for development and threats like Nb5. Black usually declines with ...a6 or ...c4, keeping a solid game.
What should Black play next?
The engine's first choice is a6, with c4 and Bd7 close behind. 5...a6 stops Nb5 and keeps the b2 pawn under pressure.
Related lines
Updated October 2026. Sources and method.