Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nd4

Blackburne shilling gambit
	a b c d e f g h 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 a b c d e f g h
	Position in Forsyth-Edwards Notation (FEN) r1bqkbnr/pppp1ppp/8/4p3/2BnP3/5N2/PPPP1PPP/RNBQK2R
	Moves: 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nd4
	ECO code: C50
	Parent: Italian game

3...Nd4? · Blackburne shilling gambit

Black violates an opening principle by moving his knight again. Black hopes to tempt White into taking the unprotected e5 pawn.

4. Nxe5?? falls into Black's trap. After 4...Qg5, forking White's knight the g2 pawn, White is in dire trouble. If White attempts to save the knight, (5. Nxf7?? Qxg2) then White has to give up the rook instead. If they try to hold onto their rook, then they must give up their queen or get mated. (6. Rf1 Qxe4+ 7. Qe2 (7. Be2? Nf3#) 7...Nxe2-+) 5. Bxf7+⩱ is the only way to stay in the game.

The gambit is a one-trick pony: as long as White avoids 4. Nxe5??, they are comfortably ahead. For this reason, Black is supposed to exclaim, "Oh my God!" to sell the illusion that they have blundered a pawn.

Black's knight is misplaced and they are falling behind in development, so White has a lot of good options. White can simply decline the gambit with 4. O-O or kick Black's knight with 4. c3 (both of these usually induce 4...Nxf3 5. Qxf3). The most critical line is 4. Nxd4.

4. Nxd4 exd4 trades knights and dislodges Black's pawn from e5. This opens up a number of tactical opportunities for White. After 4...exd4, White has an idea of playing e5 themself, e.g. 4...exd4 5. O-O Nf6 6. Re1 Bc5? 7. e5! Ng8 (only safe square for the knight). Another idea is that Qh5 can attack f7 while forking anything on the fifth rank, e.g. 4...exd4 5. O-O Bc5? 6. Bxf7+ Kxf7 7. Qh5+ Ke7 8. Qxc5+ d6 9. Qxd4 nets White two pawns.

History

This gambit is named for Joseph Henry Blackburne (1841-1924), who apocryphally used to win shillings (about £3-4 today) from amateurs in coffee shops.^[1] It is also called the Kostić gambit after Serbian grandmaster Boris Kostić (1887-1963), who was recorded to have a game in this line in 1912.^[2]

Steinitz published an analysis of the gambit in 1895, recommending 4. O-O or 4. Nxd4, but did not associate it with Blackburne.^[1]^[3]