Final position — Black is winning
Ruy Lopez: Opening Trap (Mueller–Petek)
Black wins in 10 moves with a decisive material gain. (Mueller - Petek, 1993.??.??)
The moves
| 1. | e4 | e5 |
| 2. | Nf3 | Nc6 |
| 3. | Bb5 | a6 |
| 4. | Ba4 | Nf6 |
| 5. | d4 | exd4 |
| 6. | O-O | Be7 |
| 7. | Re1 | b5 |
| 8. | Bb3 | d6 |
| 9. | Nxd4 | Nxd4 |
| 10. | Qxd4 | c5 |
How the Ruy Lopez: Opening Trap (Mueller–Petek) works
The Ruy Lopez: Opening Trap (Mueller–Petek) is a classic chess opening trap arising from the Ruy Lopez. In this line Black wins decisive material by move 10, punishing a natural-looking but losing idea from White.
The full sequence runs 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.d4 exd4 6.O-O Be7 7.Re1 b5 8.Bb3 d6 9.Nxd4 Nxd4 10.Qxd4 c5. 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 (Mueller - Petek, 1993.??.??). 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: Opening Trap (Mueller–Petek) 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.