Chess Opening Theory/1. e4/1...c5/2. Nf3/2...g6/3. d4/3...cxd4

Black takes the d-pawn. This was the idea behind 1...c5: White can retake and Black has a central pawn majority (both d- and e-pawns). In exchange, White gets open lines for development.

There are two ways to retake the pawn.

4. Nxd4 is natural. 4...Nc6 transposes into the accelerated dragon Sicilian and Black has successfully avoided facing the Rossolimo variation through the hyperaccelerated move order.

From there, the main continuations Black faces are 5. c4 or 5. Nc3. 4...Bg7 5. c4 Nc3 transposes. 4...Nf6 first, attacking e4, encourages 5. Nc3 so as to avoid facing 5. c4, though White can always play 5. f3 to keep the option of c4. 4...Nf6 5. e5? loses the pawn to 5...Qa5+.

4. Qxd5 is an alternative that avoids a straight transposition into the accelerated dragon. This attacks h8, since Black has moved their g-pawn (4...Nc3?? 5. Qxh8! or 4...Bg7 5. Qxg7!).

4...Nf6 and White has the tricky line 5. e5!? Nc6 6. Qa4 Nd5 7. Qe4 Ndb4?! 8. Bb5 Qa5?! 9. Nc3± (diagram), where e.g. 9...d5 10. exd6 Bf5 11. Qe5 f6 12. Bxc6+ Nxc6 13. Qxa5 Nxa5 14. dxe7 Bxe7 15. Nd4 Bb4.