Engine Releases and Openings for Correspondence Play

StockfishDD (version 4 - 4 cores) Komodo 5 (single core)

Correspondence Openings
     Sometime back I downloaded the nearly 167,000 archived games from Lechenicher SchachServer then made a database containing 5951 games where both players were rated over 2300. I then made an opening book based on those games.
     What openings give the best results? White’s scored best with: 1.d4, 1.Nf3, 1.c4 and 1.e4 respectively.
     By far the most popular reply to 1.d4 was 1…Nf6, but the second most popular reply, 1…d5 was slightly better for Black. Other replies by Black did not have enough games to make the statistics significant.
     Against 1.Nf3 the best results for Black were obtained with 1…d5 while the best chances against the English saw Black playing 1…e5
     If White plays 1.e4 the scores were:

1…e5 (White scored 53.7%)

1…c5 (White scored 53.0%)

1…e6 (White scored 53.6%)

1…c6 (White scored 56.0%)

     In the Sicilian, the Sveshnikov variation was Black’s most popular and best choice and in case of 1.e4 e5, White got the best results with the Scotch. In the Ruy Lopez White does best to play the Exchange Variation, but if he does not, Black’s best line is the Zaitsev Variation (also called the Flohr–Zaitsev Variation) which was a Karpov favorite and remains one of the most important variations of the Ruy Lopez. 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0–0 Be7 6.Re1 b5 7.Bb3 0–0 8.c3 d6 9.h3 Bb7

     Other Openings/Defenses:

Giuoco Piano (White scored 44.0%)

King’s Gambit (White scored 23.7%)

Caro Kann (White scored 54.9%)

Alekhine Defense (White scored 66.7%)

 

Nimzo-Indian (White scored 55.1%)

King’s Indian (White scored 58.2%)

Gruenfeld (White scored 58.6%)

QGA (White scored 54.7%)

QGD (White scored 57.6%)

     After 1.d4 d5 2.c4 Black’s best choice is 2…c6 where White scored 52.1% I was disappointed to find that my personal favorite, the Torre Attack, 1.d4 d5 2.Nf3 Nf6 3.Bg5, only appeared in three games and after 3…Ne4 all the games were drawn.
     When using any opening book or database it must be remembered that they are museums. They tell you what used to be good so it’s important to do an exhaustive engine analysis of your lines of choice to find improvements. I rarely do that because it’s too time consuming and have paid the price a few times by entering a line that was supposed to give me good chances only to have an opponent come up with an improvement.