Chess Opening Theory/1. e4/1...c5/2. Nf3/2...Nc6/3. d4/3...cxd4/4. Nxd4/4...Nf6/5. Nc3/5...d6/6. Bg5

=Classical Sicilian Richter Rauser variation= Traditionally, in the Classical Sicilian, Black aims for ...e5 or ...g6. The Richter-Rauser (also spelt Richter-Rauzer) is a way for white to combat both of these ideas. It does not completely stop either of the ideas, but it does make them less desirable. ...g6 would weaken the defense of the Black knight on f6.

6...e5 in this position would be considered winning for White and detrimental to the Black position, as after White captures the knight with '''7. Bxf6''', Black has to choose between capturing back with the g-pawn, or with the Queen:

Option 1: Taking back with 7...gxf6 is the better of the two options according to engine analysis, although it comes with White gaining an outpost for its knight after '''8. Nf5'''. Black could attempt to dislodge the knight with 9...d5, but this can be met with '''10. Qxd5'''. Exchanging Queens immediately is not good for Black, as after '''10...Qxd5 11. Nxd5, White is threatening to fork the Black King and Rook with Nc7+'''. Black is forced to exchange its Light-Squared Bishop with '''11...Bxf5 12. exf5'''. Black then castles with 12...O-O-O, and White wins a pawn.

Option 2: Taking back on f6 with the Black Queen (7...Qxf6) is the worst of the two options and gives White double the advantage. White moves his knight with '''8. Ndb5 threaten Nc7+''', forking the King and Rook. Defending with the Queen isn't feasible, as White can simply place his other knight on d5 with a nice outpost, and c7 is weak again. If White attempts to defend with the King, with either 8...Kd8 or 8...Kd7, White can play '''9. Nc7!!, sacrificing the knight, because if the Black King captures (9...Kxc7??) White can play 10. Nd5!''' forking the Black King and Queen.

However, it must be kept in mind this opening is fairly theoretical, and there are several playing options for both sides that can lead to a variety of positions.

Theory table
'''1.e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 d6 6. Bg5'''