Richter-Rauzer is the most popular attack against the classical Sicilian, which starts with 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6 6.Bg5. This is a very aggressive and sharp line played often at top-level chess.
6…e6 is the main line here. But black can also play sidelines like 6…Qb6, 6…Bd7 and 6…a6 6…e6 7.Qd2 a6 8.0-0-0 is the key position of this opening.
The most popular move is immediate 8…Bd7. But black can also kick the white bishop first with 8…h6, before playing Bd7.
Black plays 8…h6
The advantage of 8…h6 is that white’s Bishop is forced to retreat or capture on f6. But the disadvantage is that move h6 weakens the kingside, and in some lines it is helpful for white’s attack. After 8…h6 9.Be3 Bd7 10.f3 b5 11.Nxc6 Bxc6 12.Ne2 Qc7 13.Kb1 and we reach the position below.
White will try and generate kingside attack with h4-Rh3-Rg3, or simply h4-g4-g5. Black will try to create a counterplay using the open c file and advanced queenside pawns. However, with white’s attacks being quicker, black has to also pay more attention to defense.
After 8…h6 9.Be3 Be7, white has an additional option of playing 10.f4. White had to play f3 in the previous line because of Bd7-Bc6 and e4 pawn would become weak.
The line can go 10.f4 Nxd4 11.Bxd4 b5 12.Bd3 Bb7 13.Kb1 0-0 and white is ready to launch an attack with h3-g4. Notice that move h6 creates a ‘hook’ for white to attack easily.
The game is objectively equal, but the game is much easier for white to play. White’s plan of attack seems much clearer than Black’s.
Also, even after 9…Be7, white can take the slower approach with 10.f3 Nxd4 11.Bxd4 b5 12.Kb1 Rb8
White can go 13.Be3 directly or add an in-between move 13.Ba7 Rb7 14.Be3, to place black’s rook in an awkward position. After 14…Qa5 15.Nd5 Qxd2 16.Nxf6 gxf6 17.Bxd2 e5 white has a better game due to slightly weak pawn structure of black.
The f3 variation is a calmer approach compared to f4, which lead to sharp game and a potentially strong attack.
Just to add a sideline, after 8…h6 white can also play less common 9.Nxc6 bxc6 10.Bf4 d5 11.Qe3 Bb4 12.Be2 0-0 13.e5 Nd7 14.Qg3 giving black a strong center, but taking an opportunity to create an attack on kingside with threats like Bxh6.
Black plays 8…Bd7
This is the main line after which, white again has option of playing either 9.f3 or 9.f4. The main difference is that move h6 has not been played, so white will have a possibility to capture on f6.
The main line is 9.f4 b5 10.Bxf6 gxf6 11 Kb1 b4 12.Nde2 Qb6 13.Nxc6 Bxc6 14.f5
Black’s king will remain in the center, but safe due to the central pawns. Sample line can go 14…e5 15. Ng3 h5 16.h4 Bh6 17.Qe2 Ke7
White gives up the h5 pawn, but will have a strong counter attack on the queenside with a5-a4.
Instead of 11…b4, black can directly go 11…Qb6, but after 12.Nxc6 Bxc6 13.Qe1, white threatens Nd5. By playing 11…b4, black avoids this possibility.
The other line can go 9.f3 Nxd4 10.Qxd4 Be7 11.Kb1 b5 with a more positional type of a game,
Or 9.f3 Be7 10.h4 h6 11.Be3 h5 12.Kb1 Qc7 with a sharp game and attack on opposite wings.
And finally, instead of 7.Qd2, white can also go for less popular move like 7.Bb5.
The line goes 7…Bd7 8.Bxc6 bxc6 9.Qf3 h6 10.Bh4 Qb6 11.0-0-0 Nb3 with a double edged position.
As we have seen, in most lines, black’s king remains in the center but still safe. Also, many of the lines include attack on opposite wings. White’s position is usually easy to play because the common plan is to castle Queenside and generate a kingside attack.
Black has to be ready to play typical positions with king in the center and doubled f-pawns in many lines.
Richter-Rauzer has a very dense theory, and it is recommended to study the opening properly before playing in serious games.