Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. c3/3...Nf6/4. d4/4...Nxe4/5. d5/5...Bc5

After 5. d5, Black can gambit their knight on c6 with 5...Bc5, the Vuković gambit or Fraser defence. Black's c5 bishop and e4 knight both target White's f2 pawn.

The Vuković gambit is so bloodthirsty that if Frankenstein and Dracula ever take a break from the Vienna game, expect to see them here.^[1] It leads to a very chaotic and cut-throat middle game: both Black and White must navigate a series of only moves to keep the game competitive.

The advantage for Black is that these tactical middle games, with White's king exposed on e2, are far from the calm, central development that White hoped for when they played 3. c3, however Black does gambit a minor piece and so it is up to them to prove they have compensation. Of course, navigating a cliff's edge of only-moves is only precarious if the other side can pick up when you mis-step.

Trying to defend f2 with 6. Qe2? fails to 6...Nxf2. White must instead accept the offered knight with 6. exc6 and brave the cliff edge, or make a huge concession to Black with 6. Be3?!.

After 6...Bxf2+□ (6...Nxf2? loses to 7. Qd5. If Black takes the rook, they will lose their bishop and their knight gets stuck) 7. Ke2, black must retreat the bishop with 7...Bb6□.

If instead they try 7...bxc6? then Black can't keep the bishop and knight defended (8. Qa4 f5 9. Nbd2). Before 7. Bb6 was discovered, 7...bxc6? was thought to be Black's only continuation and this gambit was thought to be refuted by 8. Qa4.^[2]:49-53[3]

Then, White's only move is 8. Qd5!□, defending c6 and attacking e5 and the knight on e4. Now after 8...Nf2, attacking the rook, White has the illusion of choice: save the rook with 9. Rg1, counterattack with 9. cxb7, supported by the queen on d5, or take the e5 pawn with check 9. Qxe5+?.

The e5 pawn is poisonous of course. If 9. Qxe5+? Kf8, now 10. cxb7? doesn't work (10...Bxb7) and after 10. Rh1 Ng4 (wins tempo on the queen) 11. Qf4 dxc6 the knight is defended by Black's light square bishop. White might have been hoping to support 10. Be3 to eliminate Black's powerful bishop, but Black can simply play 10...Nxh1.

Should White save the rook 9. Rg1, Black must know to castle 9...O-O, allowing 10. cxb7 Bxb7 11. Qxb7 as Black recognises their queenside is stable, and they must also know 11...Qf6□. 11...Qf6 allows Rab1 Qd5 to be met by c6. If Black does not castle but prevents cxb7, then 9...bxc6? 10. Qxe5+□ (this time it's not poisonous) Kf8 11. Nd4□ (interrupts bishop's vision of knight) Ng4 12. Qf4 and Black's attack is diffused. Needless to say, anything other than 10. Qxe5+ or 11. Nd4 is losing for White.

Should White give up their rook and counterattack instead 9. cxb7, 9...Bxb7 10. Qxb7 Nxh1. Black has the rook and two pawns but is down two minors and a pawn, and the position is still chaotic. White can follow with 11. a4, planning a5, b4 to kick the bishop, and trap Black's knight.

White may try 6. Be3?! trading bishops. 6...Bxe3 7. fxe3 avoids these complications, but the resulting positions are very favourable for Black. This gives Black's knight the chance to escape, and though White can win a pawn with 7...Ne7 (planning Nf5) 8. Nxe5, White has difficulty developing and keeping their backwards e3 pawn defended.

For example, 8...O-O 9. Bc4 (defending d5 and trying to castle) Nf5 (attacking e3) 10. Qf3 Ned6 (attacking bishop on c4) 11. Bb3 Re8 (attacks knight on e5 and pins knight to pawn) and White is cooked.

For explanation of theory tables, see theory table and for notation, see algebraic notation.

1.e4 e5 2. Nf3 Nc6 3. c3 Nf6 4. d4 Nxe4 5.d5 Bc5

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Wikipedia has related information at Ponziani Opening

• Taylor, Dave; Hayward, Keith (2010). Play the Ponziani. London: Everyman Chess. ISBN 1 8574 4620 8.