Petrov's Defense

Petrov's Defense meets the King's Gambit with 2...Nf6, ignoring the f4-pawn and attacking e4 instead. The move was suggested by Petroff, and the reference literature likens it to a Latvian Gambit with colors reversed. It differs from the other ways of declining in one important respect: the knight on f6 stands on the d8–h4 diagonal, so the usual reply to fxe5, the queen check on h4, is no longer available. White's capture on e5 is therefore a real option at once, and the engine ranks 3. fxe5 first, giving White a slight edge.

In practice 3. Nf3 is the most common answer, developing and keeping the gambit structure, while 3. Nc3 defends e4 and transposes to the Vienna Gambit. 3. fxe5 is the third choice, ahead of 3. Bc4, which leads to the Greco Gambit line of the Bishop's Opening: Berlin Defense and is the only main continuation after which Black scores better than White. The line is a fringe choice, seen mostly in online and amateur play, where White scores somewhat better overall.