Trying to keep the pawn with …b5
1.d4 d5 2.c4 dxc4 3.e3 b5 4.a4 c6 5.axb5 cxb5 6.Qf3
- The mistake
- Defending the extra pawn with 3…b5.
- Why it costs
- 6.Qf3 hits the rook on a8 and f7 together, down a diagonal that Black's own pawn moves opened — b7, c6 and d5 are all empty. Nothing saves everything, and the extra pawn was never keepable to begin with. It is the oldest trap in the opening and it still works.
- Instead
- 3…Nf6 and …e6, and let White spend a move on Bxc4. …a6 and …b5 have their place later, once the rook on a8 is not the thing being forked.