Final position — Black is winning
Marshall Trap (Petrov's Defense)
Black wins in 18 moves with a decisive material gain.
The moves
| 1. | e4 | e5 |
| 2. | Nf3 | Nf6 |
| 3. | Nxe5 | d6 |
| 4. | Nf3 | Nxe4 |
| 5. | d4 | d5 |
| 6. | Bd3 | Bd6 |
| 7. | O-O | O-O |
| 8. | c4 | c6 |
| 9. | cxd5 | cxd5 |
| 10. | Nc3 | Nxc3 |
| 11. | bxc3 | Bg4 |
| 12. | h3 | Bh5 |
| 13. | Rb1 | b6 |
| 14. | Rb5 | Bc7 |
| 15. | Rxd5 | Qxd5 |
| 16. | Bxh7+ | Kxh7 |
| 17. | Ng5+ | Qxg5 |
| 18. | Bxg5 | Bxd1 |
How the Marshall Trap (Petrov's Defense) works
The Marshall Trap (Petrov's Defense) is a classic chess opening trap arising from the Petrov's defence. In this line Black wins decisive material by move 18, punishing a natural-looking but losing idea from White.
The full sequence runs 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5 6.Bd3 Bd6 7.O-O O-O 8.c4 c6 9.cxd5 cxd5 10.Nc3 Nxc3 11.bxc3 Bg4 12.h3 Bh5 13.Rb1 b6 14.Rb5 Bc7 15.Rxd5 Qxd5 16.Bxh7+ Kxh7 17.Ng5+ Qxg5 18.Bxg5 Bxd1. Each move looks reasonable, which is exactly why the trap is so effective over the board — White walks into it while trying to play "normal" developing moves.
Recognising this pattern early lets you either spring it as Black or calmly sidestep it when you are White.
Practice this trap move-by-move
Open the Marshall Trap (Petrov's Defense) in the Trapsterapp to play it out on a live board, drill it in practice mode, and learn how to avoid it when it's set for you — along with the full library of chess traps and gambits, fully offline.