Two Knights Defense, Traxler Counterattack, Bishop Sacrifice Line

Instead of grabbing the exchange with 5. Nxf7, which invites 5...Bxf2+ and a wild king hunt, White uses the bishop to take on f7 with check. White gains a pawn, Black loses the right to castle, and the counterblow against f2 never gets started. This is the choice of most modern masters and is regarded as the most reliable way to keep an edge. The engine rates White's advantage as clear. Black does get the half-open f-file and some lead in development, since the bishop on f7 is attacked and must move again.

Black has two king moves, played about equally often. 5...Kf8 is slightly more common but scores poorly online, with White winning well over half the games. 5...Ke7, the engine's first choice, gives results close to even. After 5...Ke7 White usually retreats with 6. Bd5, while 6. Bb3 and 6. b4 are the other options. The usual plan for Black is to bring the queen to g6 by way of e8 and use the f-file. Draws are rare.