Final position — White is winning
Petrov's Defence: Knight Fork
White wins in 7 moves with a decisive material gain. (Frank - Schiller, New York 1970)
The moves
| 1. | e4 | e5 |
| 2. | Nf3 | Nf6 |
| 3. | d4 | exd4 |
| 4. | Nxd4 | Qe7 |
| 5. | Nb5 | Nxe4 |
| 6. | Nxc7+ | Kd8 |
| 7. | Nxa8 | Nc3+ |
How the Petrov's Defence: Knight Fork works
The Petrov's Defence: Knight Fork is a classic chess opening trap arising from the Petrov's defence. In this line White wins decisive material by move 7, punishing a natural-looking but losing idea from Black.
The full sequence runs 1.e4 e5 2.Nf3 Nf6 3.d4 exd4 4.Nxd4 Qe7 5.Nb5 Nxe4 6.Nxc7+ Kd8 7.Nxa8 Nc3+. Each move looks reasonable, which is exactly why the trap is so effective over the board — Black walks into it while trying to play "normal" developing moves.
This pattern is well known from master and correspondence play (Frank - Schiller, New York 1970). Recognising it early lets you either spring it as White or sidestep it as Black.
Practice this trap move-by-move
Open the Petrov's Defence: Knight Fork 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.