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

With 4. d4, White ignores the attack on the e-pawn and counterattacks Black's central pawn on e5. Black's best move is to choose a central pawn to capture, 4...exd4 or 4...Nxe4, though White has ways to recover the pawn. 4...d5 is also playable.

4...exd4 5. e5 kicks the f6 knight and prevents 5...Nxe4. This is a transposition into the Göring Gambit declined with Nf6.

After 5... Nd5 6. Qb3 Nb6, White recaptures 7. cxd4 and the position is a toss up. White has two pawns in the centre but Black can begin to chip away at them with d6.

After 5... Ne4 6. Qe2, Black must decided how to protect their knight. He either concedes the centre (e.g. 6...Nc5 cxd4 ±), or tries to hold onto their knight with d5 and f5 in either order. Both look counter-intuitive as e5 taking en passant creates a pin on Black's knight and White is threatening f3 or Nbd6. This is indeed a problem after 6...d5!? 7. exd6 e.p. f5 8. Nxd4 Nxd4 9. cxd4 Bxd6 10. f3.

6...f5! instead was the recommendation of Lasker,^[1]:11-18 and creates some tactically interesting middle games with opportunities for both sides after 7. exf6 e.p. e5 and either 8. Nbd2 or 8. Nxd4.

After 4...Nxe4, White is advised not to recapture on e5 straight away as 5. dxe5?^[2] Bc5! (bishop and knight coordinate against f2) 6. Be3 Bxe3 7. fxe3 and Black's position is very pleasant.

Instead White can play 5. d5 to kick the c6 knight away from protecting e5, then after 5...Ne7 6. Nxe5 (White recaptures the pawn) Ng6 (d6? Bb5!) 7. Nxg6 hxg6 8. Bd3 the position is perhaps even.

Alternatively, Black can answer 4...Nxe4 5. d5 with 5...Bc5, the Vuković gambit or Fraser defence, where Black's bishop and knight both target the f2 pawn. This gambits Black's knight for two pawns and 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.

Other fourth moves for black include 4...d5. This presents White with several options for how to proceed: 5. exd5?! still fails due to 5...Qxd5 and no Nc3 to chase it away. Taking the e5 pawn (5. dxe5 or 5. Nxe5) allows for some trades and the centre to open. 5. Bb5 is best for White here: pinning the c6 knight and so threatening Nxe5.

4...d6?!, to defend e5, is unambitious. It allows White to develop and defend their e4 pawn with Bd3, giving them the big centre they want unchallenged, and to kick the knight with d5.

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

1.e4 e5 2. Nf3 Nc6 3. c3 Nc6 4. d4

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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.