Stockfish’s Opening Repertoire

July 24, 2022 Matthew Sadler 4 comments

This article supplements a series of videos about Stockfish’s opening repertoire which appeared on the “Silicon Road to Chess Improvement” YouTube site ( This article provides an overview of Stockfish’s main openings; for all the detail and many surprises(!) take a look at the video series! See for a previous article on Komodo Dragon’s opening repertoire which also goes into the evolution of engine opening play since AlphaZero!

This series of videos used the development version of Stockfish from 13th July 2022 ( The pgn files which I used to produce the videos are shared here:

Let’s start off with Stockfish’s view of best play for both sides from the starting position. If you followed the video series on Komodo Dragon’s and Koivisto’s repertoire, it may seem eerily familiar!


1.e4 e5

2.Nf3 Nc6 3.Bb5 Nf6 4.0–0 Nxe4 5.Re1

Once again, this line of the Berlin comes out as best play for both sides from the starting position!

5…Nd6 6.Nxe5 Be7 7.Bf1 Nxe5 8.Rxe5 0–0 9.d4 Bf6 10.Re1 Re8 11.Bf4 Rxe1 12.Qxe1 Ne8 13.c3 d5

Position after 13…d5

The same line as Komodo Dragon and Koivisto!


14.Bd3 g6 15.Nd2 Ng7 16.Nf3 was Koivisto’s main line! (16.Qe2 c6 17.Re1 Bf5 18.Bxf5 Nxf5 19.Nf3 Ng7 20.Be5 Bxe5 21.Nxe5 Qd6 22.Qf3 f6 23.Ng4 Re8 24.Re5 Kf7 25.Nh6+ Kf8 26.Ng4 Kf7 27.Nh6+ Kf8 28.Ng4 Kf7 ½–½ (28) Wang,H (2744)-So,W (2776) Stavanger 2022) 16…Bf5 17.Bxf5 Nxf5 18.Qd2 a5 19.Re1 Nd6 20.g3 Ne4 21.Qc2 a4 22.Nd2 Nd6 23.a3 h5 24.h4 c6 25.Bxd6 Qxd6 26.Nf3 b5 27.Qd3 Qd7 28.Ne5 Bxe5 29.Rxe5 0.36

14…Nd6 15.Qe2 Bf5 16.Re1 c6 17.Nb3

17.Qf3 was Komodo Dragon’s line! 17…Ne4 18.Nxe4 Bxe4 19.Qg3 Bg6 20.Bc7 Qd7 21.Qd6 Qxd6 22.Bxd6 Bf5 23.f3 h5 24.Kf2 g6 25.g3 a5 26.Bf4 g5 27.Bd6 Kg7 28.h3 h4 29.g4 Be6 0.29


Predecessor: 17…h6 18.Qf3 Bg6 19.Nc5 Ne4 20.Nd3 a5 21.Qe3 Bf5 ½–½ (21) Ress,J (2303)-Almeida,R (2223) LSS email 2021

18.Nd2 Bg5 19.Qf3 Bxf4 20.Qxf4 Qd7 21.h4 h6 22.Re3 Rd8 23.Be2 Be6 24.Bd3 Bf5 25.Bf1 Be6 26.Nf3 f6 27.Nh2 Bf5 28.Be2 Nc4 29.Bxc4 dxc4 30.Re1 Be6 31.Nf1 0.29

Stockfish’s choice against 1.d4 also seems very familiar: it’s AlphaZero’s favourite Ragozin! Indeed, Stockfish’s main line follows a number of Stockfish 8 – AlphaZero games!


1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Bb4

Position after 4…Bb4: The Ragozin.

5.Bg5 h6 6.Bxf6 Qxf6 7.e3 0–0 8.Qb3 c5 9.cxd5 exd5 10.dxc5 Bxc3+ 11.Qxc3 Qxc3+ 12.bxc3 Nd7 13.Rd1 Nf6 14.Nd4 Bd7 15.f3 Rfc8 16.Nb3 Ba4 17.Rd4 Bxb3 18.axb3 Rxc5 19.Kd2

Position after 19.Kd2

Many Stockfish 8 – AlphaZero games were played in this variation – amazing how little some best choices for engines have changed since that match!


19…Ra5 was AlphaZero’s choice that also led to many draws.

20.Bd3 Rac8 21.Rc1 R8c7N

Relevant: 21…Kf8 22.g4 Ke7 23.h4 g6 24.b4 axb4 25.Rxb4 R8c7 26.Rcb1 Rxc3 27.Rxb7 h5 28.g5 Nd7 29.Rxc7 Rxc7 30.f4 Ra7 31.Bc2 Kd6 32.e4 dxe4 33.Bxe4 Ra4 34.Ke3 Ra3+ 35.Kd4 Rh3 36.Rh1 Rg3 37.Rd1 Nf8 38.f5 Rh3 39.Ra1 gxf5 40.Ra6+ Ke7 41.Ra7+ Kd6 42.Ra6+ Ke7 43.Ra7+ ½–½ (43) Swiercz,D (2647)-Caruana,F (2800) Riga 2021

22.Rc2 Kf8 23.h4 g5 24.hxg5 hxg5 25.Ra4 Ke7 26.b4 axb4 27.cxb4 Rxc2+ 28.Bxc2 Kd6 29.Bb3 Kc6 0.13

How about 1.c4?


Just like AlphaZero and pretty much every other engine, Stockfish wants to meet 1.c4 with 1…e5, heading for a reversed Sicilian.

1…e5 2.g3

All the engines want to follow up 1.c4 in this way.

2…Nf6 3.Bg2 Bc5 4.d3 Nc6

Most engines prefer …c6 systems.

5.Nc3 0–0 6.a3 a5 7.e3 d6 8.Nge2 Ne7 9.d4 Ba7 10.0–0 c6

Position after 10…c6

11.b3N Predecessor: 11.b4 Bg4 12.h3 Be6 13.Qd3 h6 14.Bb2 Ng6 15.f4 e4 16.Nxe4 Nxe4 17.f5 d5 18.fxe6 f5 19.cxd5 cxd5 20.Qb5 Qg5 21.Rf3 Nd2 22.Qxd5 Ne7 23.Qxb7 Rfb8 24.h4 Qf6 25.Qd7 Rd8 26.Qb5 Nxf3+ 27.Bxf3 Qxe6 28.Bxa8 Qxe3+ 29.Kh2 Rxa8 30.Rf1 axb4 31.axb4 Rc8 32.Bc1 Qe4 33.Rf4 Qe6 34.Qd3 Nd5 35.Rxf5 Nxb4 36.Qf3 Bb8 37.d5 Qe7 38.Kh3 Rc2 39.Ba3 Bd6 40.Nd4 Ra2 Vallejo Pons,F (2708)-Deepan Chakkravarthy,J (2476) Pattaya 2015 1–0

11…Re8 12.h3 e4 13.d5 cxd5 14.Nb5 Bc5 15.Rb1 Bd7 16.Bb2 dxc4 17.Nxd6 Bxd6 18.Qxd6 Be6 19.Qxd8 Raxd8 20.Bxf6 gxf6 21.bxc4 Bxc4 22.Rfe1 b5 23.Bxe4 Bxe2 24.Rxe2 Nd5 25.Bxd5 Rxd5 26.Rc2 Rb8 27.Rb3 Kg7 28.Rc7 Rb6 29.Kf1 Kg6 30.Re7 Re5 31.Rd7 Rc5 32.Kg2 h5 33.Rd8 Rb7 34.Kf1 b4 35.axb4 Rcb5 36.Rd2 axb4 37.Ke2 f5 38.Kf1 R5b6 39.Rdb2 Rb5 0.07

1.Nf3 obviously has many transpositional possibilities but also some original features:


d=68, 1269932Mn

1…d5 2.g3

Much to my surprise, Stockfish doesn’t go for the transposition with 2.d4 but opts for a pure Reti!


Position after 2…g6

A line I first noticed when Anand used it against Magnus Carlsen in the 1st game of their first World Championship match.

3.Bg2 Bg7 4.d4 Nf6 5.c4 c6 6.cxd5 cxd5 7.Nc3 Nc6 8.Ne5 Bd7 9.Bf4 e6 10.Qd2 Nxe5 11.Bxe5 0–0 12.0–0 Qe7N

12…Bc6 13.Rfd1 Rc8 14.Rac1 Nd7 15.Bxg7 Kxg7 16.e3 Nb6 17.b3 Qe7 18.Qb2 Kg8 19.h4 h5 20.Qd2 Qb4 21.Bf1 a5 22.Bd3 Kg7 23.Ne2 Qxd2 24.Rxd2 Ra8 25.a3 Nc8 26.Rdc2 Nd6 27.Rc5 Kf6 28.f3 Ke7 29.Kf2 Rfc8 30.Nf4 Kd7 31.g4 a4 32.b4 b6 33.R5c3 Bb5 34.gxh5 Rxc3 35.Rxc3 gxh5 36.Bxb5+ Nxb5 37.Rd3 Rg8 38.e4 dxe4 39.fxe4 Rg4 40.Nxh5 Rxh4 41.Ng3 Rh2+ 42.Ke3 Yermolinsky,A (2625)-Almasi,Z (2650) Groningen 1998

13.Rac1 b5 14.Nb1 Rfc8 15.Rxc8+ Rxc8 16.Rc1 Rc4 17.b3 Rxc1+ 18.Qxc1 Ne8 19.e3 Bf8 20.Nd2 Qd8 21.e4 Nf6 22.Qc3 Be7 23.Bxf6 Bxf6 24.exd5 Qb6 25.dxe6 Bxe6 26.Nf3 b4 27.Qc5 Qa6 28.d5 Bf5 29.Qc6 Qxc6 30.dxc6 Kf8 31.Kf1 Ke7 32.Nd2 Bd4 33.Ke2 f6 34.c7 0.25

Finally let’s round off this overview with some crazy stuff starting with a Richard Rapport favourite!



d=62, 137039Mn

1…d5 2.d4 Nf6 3.Bf4 a6 4.e3 e6 5.g4 Bb4 6.Nge2 0–0 7.a3 Be7 8.g5

Position after 8.g5

This line is recommended in Simon Williams’ book on the Jobava London System (into which this transposes) but only mentions 8…Nh5.



9.h4 c5 10.Bg2 Nc6 11.Rg1 Re8 12.h5 cxd4 13.exd4 Bxg5 14.Bxg5 Qxg5 15.Bxd5 Qh6 16.Bf3 e5 17.Bxc6 bxc6 18.Qd2 Qxd2+ 19.Kxd2 Nf6 20.dxe5 Rxe5 21.h6 Bg4 22.Nf4 g6 23.Rae1 Rxe1 24.Rxe1 Kf8 25.Nd3 Bf5 26.Ne5 Rd8+ 27.Kc1 Re8 28.Kd2 c5 29.f3 Ng8 30.Na4 f6 31.Nc4 Rxe1 32.Kxe1 Bxc2 33.Nxc5 Nxh6 34.Ne3 Bb1 35.Nxa6 Nf5 36.Nxf5 Bxf5 37.b4 Ke7 38.Nc5 Kd6 Tologontegin,S (2358)-Aleksandrov,A (2574) Cheliabinsk 2021 ½–½

9…Bxg5 10.Rg1 Bxf4 11.Nxf4 Qh4 12.Qf3 dxe4 13.Qxe4 Qh6 14.Qe3 Nc6 15.0–0–0 Ne7 16.Bd3 Nf6 17.Kb1 Ng6 18.Nce2 Re8 19.Bxg6 fxg6 20.Qe5 Rf8 21.Qxc7 Qxh2 22.f3 Qf2 23.Rgf1 Qh4 24.Rh1 Qf2 0.00


Just like Komodo Dragon, Stockfish also likes the sharp plan of occupying the centre with both pawns though it plays it in a slightly different way…

1.b3 e5 2.Bb2 Nc6 3.e3 d5 4.Bb5 Bd6 5.f4 f6 6.Qh5+ g6 7.Qh4 exf4

Position after 7…exf4

8.Nc3 Nge7

8…a6 9.Bxc6+ bxc6 10.exf4 d4 11.Ne4 c5 12.Nxd6+ Qxd6 13.0–0–0 Ne7 14.Nf3 Bb7 15.Rde1 0–0–0 16.Rhf1 Nd5 17.f5 g5 18.Qg3 Rde8 19.Kb1 a5 20.Ba3 a4 21.Re6 Rxe6 22.fxe6 Nf4 23.Re1 Re8 24.e7 d3 25.c4 Rxe7 26.Rxe7 Qxe7 27.Qf2 Qe2 28.Qxc5 Bxf3 29.Qf8+ Kd7 30.Qf7+ Kc6 31.gxf3 Qd1+ 32.Kb2 Qxd2+ 33.Kb1 Qd1+ 34.Kb2 Qc2+ 35.Ka1 Qc3+ 36.Kb1 Qe5 37.Bc1 axb3 38.axb3 Bluebaum,M (2642)-Grischuk,A (2758) INT 2022 ½–½ (90)

9.Qxf6 Rf8 10.Qh4 fxe3 11.dxe3 Qd7 12.Nf3 Qg4 13.Qf2 Bd7 14.0–0–0 0–0–0 15.Kb1 Kb8 16.Nxd5 Nxd5 17.Rxd5 a6 18.Bc4 Be6 19.h3 Qe4 20.Rxd6 cxd6 21.Ng5 Qxc4 22.Qxf8 Rxf8 23.bxc4 Bxc4 24.Nxh7N

24.Ba3 Kc7 ½–½ (24) Sneppe,H (2436)-Iermito,S (2424) ICCF email 2020

24…Rf1+ 25.Rxf1 Bxf1 26.Nf8 Bxg2 27.Nxg6 Bxh3 28.Nf4 Bf1 29.Bd4 Kc7 30.Kb2 Bc4 31.a3 Bf7 32.Kc3 Na5 33.Nd3 Bg8 34.Nb2 b6 35.Nd3 Nb7 36.Bf6 Kc6 37.Nf2 a5 38.Ne4 Kd5 39.Ng5 Nc5 -0.08

4 Comments on “Stockfish’s Opening Repertoire

  1. Fascinating stuff! Thanks for sharing GM Sadler!
    Berlin and Ragozin, rock solid 🙂
    Interesting that as white Stockfish seems to prefer 3. Nf3 over 3. Nc3 after 1. d4 Nf6 2. c4 e6. Reminds me of GM Pia Cramling’s repertoire that you superbly analyzed and discussed in Chess for Life.
    Do you think Stockfish prefers 3. Nf3 to avoid the Nimzo?

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