Blackburne-Kostić Gambit

The Blackburne-Kostić Gambit, better known as the Blackburne Shilling Gambit, arises after 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nd4. Black breaks a basic opening principle by moving the same knight twice. The move abandons the defense of e5 and invites White to grab the pawn. It amounts to a single trap rather than a positional concept, and its value depends almost entirely on whether White takes the bait.

The trap is 4. Nxe5? Qg5, which attacks both the knight on e5 and the pawn on g2. Saving the knight with 5. Nxf7? fails to 5...Qxg2 6. Rf1 Qxe4+, and then 7. Be2 Nf3# is mate, while 7. Qe2 Nxe2 costs White the queen. White's only reasonable try is 5. Bxf7+, which gives back material to limit the damage. In online games 4. Nxe5 is the second most frequent reply, and Black wins the large majority of those games. That result accounts for the gambit's respectable overall score on Lichess, where Black slightly outscores White despite its poor theoretical standing.

If White ignores the pawn, Black's position has clear drawbacks: the d4-knight is exposed and development lags behind. The most common and most critical answer is 4. Nxd4 exd4, which trades knights and pulls Black's pawn off e5, opening tactical chances on the e-file and against f7. After 5. O-O Nf6 6. Re1 Bc5?, the thrust 7. e5 forces the knight back to g8. After 5. O-O Bc5? instead, 6. Bxf7+ Kxf7 7. Qh5+ Ke7 8. Qxc5+ d6 9. Qxd4 leaves White two pawns ahead. Quieter options are 4. O-O and 4. c3, both of which usually lead to 4...Nxf3 5. Qxf3, with a lead in development for White. The engine assesses the starting position as a clear advantage for White and ranks 4. Nxd4 first, with 4. O-O and 4. a4 as alternatives.

The opening is named for Joseph Henry Blackburne. An apocryphal story says he used it to win shillings from amateurs in coffee houses. The other name refers to the Serbian grandmaster Kostić, who is recorded as playing the line in 1912. Steinitz published analysis of 3...Nd4 in 1895 and recommended 4. O-O or 4. Nxd4, though he did not link the move to Blackburne.