Final position — Black delivers mate
Ruy Lopez: Back-Rank Mate (Duncan–Wall)
Black wins in 12 moves by checkmate. (Duncan - Wall, Dayton 1984)
The moves
| 1. | e4 | e5 |
| 2. | Nf3 | Nc6 |
| 3. | Bb5 | a6 |
| 4. | Bxc6 | dxc6 |
| 5. | O-O | Qd6 |
| 6. | d4 | Bg4 |
| 7. | Bg5 | f6 |
| 8. | Be3 | O-O-O |
| 9. | h3 | h5 |
| 10. | hxg4 | hxg4 |
| 11. | Nh2 | exd4 |
| 12. | Bd2 | Qxh2# |
How the Ruy Lopez: Back-Rank Mate (Duncan–Wall) works
The Ruy Lopez: Back-Rank Mate (Duncan–Wall) is a classic chess opening trap arising from the Ruy Lopez. In this line Black delivers checkmate on move 12, punishing a natural-looking but losing idea from White.
The full sequence runs 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.O-O Qd6 6.d4 Bg4 7.Bg5 f6 8.Be3 O-O-O 9.h3 h5 10.hxg4 hxg4 11.Nh2 exd4 12.Bd2 Qxh2#. 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.
This pattern is well known from master and correspondence play (Duncan - Wall, Dayton 1984). Recognising it early lets you either spring it as Black or sidestep it as White.
Practice this trap move-by-move
Open the Ruy Lopez: Back-Rank Mate (Duncan–Wall) 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.