The London's poisoned b-pawn is lesson 7 of 10 in Brilliant sacrifices 2: gambits, an opening course suited to players rated around 1200 (improving players). London System, Poisoned Pawn Variation, D02. White leaves b2 and aims a knight at c7. It has 3 interactive exercises: 3 find-the-move puzzles. You play every move on a board and get feedback straight away. The lesson is free.
What this lesson explains
This is the London System. Black's queen on b6 hits b2. White does not guard it. White develops and lets the queen take. About 221,000 rated games on Lichess have reached this position.
Nc3! The knight develops and leaves b2. If Qxb2, the knight jumps to b5 and threatens c7.
After Qxb2 and Nb5, White threatens Nc7 check, forking the king and the rook. Black must defend, and the queen on b2 is far from home. The engines say White has enough for the pawn.
Recap.
In the London, Qb6 often hits b2.
Nc3 leaves b2 and prepares Nb5.
After Qxb2, Nb5 threatens Nc7 check.
Black's queen gets into trouble far from home.
What you practise
First play the line. You are White: play the moves of the London System, up to the moment of the sacrifice.
Your turn: find the sacrifice. Black's queen hits b2. Do not guard it. Develop a knight that can jump to b5.
Black does not take b2. Black plays c4 instead, and the queen still hits b2. Now guard it.
Worked examples
First play the line. You are White: play the moves of the London System, up to the moment of the sacrifice. Good. Black answers Qb6. Now the position is ready for the sacrifice.
Your turn: find the sacrifice. Black's queen hits b2. Do not guard it. Develop a knight that can jump to b5. That is the poisoned b-pawn. After Qxb2, Nb5 hits c7, and the queen is in danger.
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