Why is 5. Nc3 preferred over 5. f3 in the Open Sicilian? The statistics at move 5 seem amazing for White, slightly better than Nc3. I was wondering how White can "get away" with the plan to play c4 before Nc3, achieving even more control of the center. So what exactly is White giving up? Black can try to break through before c4 is played by 5...e5 6. Nb3 d5, but this position does not seem very critical to me, at least less critical than some variations of the Najdorf (I may be wrong).

[fen ""]

1. e4 c5 Nf3 d6 d4 cxd4 Nxd4 Nf6 f3 e5 Nb3 d5 Bg5 d4 c3 Nc6 Bb5


If Black does not play ...e5 we get a cozy setup with Be3, Be2, 0-0, Qd2 and centralising the rooks incoming and Black cannot do much about it.

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1. e4 c5 Nf3 d6 d4 cxd4 Nxd4 Nf6 f3 e6 c4 Be7 Nc3
The move 5.f3 is an interesting one and worth a try for two reasons:


Avoiding heavy theory.
Tricking some Najdorf or Dragon players who are not keen to play the Maroczy bind with c4. 


However, Black has a few ways to respond. One response seems very tricky by directly exploiting the weakness created by f3 (and avoiding the Maroczy bind).

[FEN ""]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.f3 e5 6.Nb3 a5!? 7.c4? (7.Bb5 {is better}) Nxe4! 8.fxe4 Qh4+ 9.Kd2 a4 {and Black wins back the piece with some advantage}




Black seems to be fine by playing e5 and d5, without pushing further to d4 as played recently by Giri, Nakamura, Areshchenko.

[fen ""]

1. e4 c5 2. Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.f3 e5 6. Nb3 d5 7.Bg5 Be6 8.Bxf6 gxf6 9.exd5 Qxd5 10.Qxd5 Bxd5 {and the pair of bishops offsets the pawn weaknesses.}




Update: If following the good arguments of @Scounged, Black is not afraid to enter the Maroczy bind, there is a favorable version. Black plays 5...Nc6 and if White continues by 6.c4 Black replies with 6...Qb6 disrupting White's play, followed by g6. Here is an illustrative game:

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[title "D'Amore, Carlo (2456) vs. Sutovsky, Emil (2664), EU-chT, 2001"]

1. e4 c5 2. Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.f3 Nc6 6.c4 Qb6 7.Nc2 g6 8.Nc3 Bg7 9.Qd3 (9.Rb1 {is probably more promising for White but there is a fun variation} 9...Ng4!? 10.Qd2! (10.fxg4 Bxc3) Bxc3 11. Qxc3 Qf2 12.Kd1 O-O) 9...Nd7 10.Nd5 Qd8 11.Be2 Nc5 12.Qa3 f5! 13.exf5? (13.O-O) Bxf5 14.Nde3 Qb6 15.Nxf5 gxf5 16.Rb1 Nd4 17.Nxd4 Bxd4 18.Be3 Ne6 19.Bxd4 Nxd4 20.Qa4+ Kf7 21.c5 Qxc5 22.Qc4+ Qxc4 23.Bxc4+ Kf6 24.Kf2 Rac8 25.Bd3 e5 26.g4 fxg4 27.fxg4 d5 28.Rbd1 h5 29.g5+ Kxg5 30.Rhg1+ Kf4 31.Rg7 Rhf8 32.Bg6 Kg5+ 0-1