Opening Repertoire Selection Using a Chess Database

by VP Henry Rankin

Choosing an opening Repertoire is no small task for any chess player. Personal tastes, psychological comfort, and general opening knowledge all come into play. Using an opening database to help provides for a more reasoned approach to explore better fitting choices. What follows is my effort to choose a repertoire that is based on analysis.

I used a chess database containing 7,140,369 Games, and then applied 2 filters.

The first filter was for all games from December 10, 2019 to December 10,2020. This filter was applied after the database wasbrought up to date with files containing the games for the website, www.thisweekinchess.com. After that, I filtered so that both the white player and the black player had a rating greater than or equal to 2200. This left me a database consisting of 105,555 games. I converted the results of the filtered database to appear as a tree with scoring percentages ofor each line the following are the results.

WARNING: Because the results are based on games played in 2020, the results reflect rapid play, and therefore might be somewhat different once classical time controls return.

I. Overall Results.

White scores more than 56% of all possible points (½ for draw, 1 for win) when starting with e4 and Black answers. In line 2, we see that 1.Nf3 scores very well. Does this mean opening for e4 is best? The results would suggest the answer to be no. Let’s take a look at the Sicilian Defense for example.

Note that in total, White scores only at 51.2%, when all Sicilian lines are considered. Given that Black has the choice of playing the second move, knowing the Sicilian Defense by Black saves him five out of 100 points in tournament play. The semi fashionable Nc3 line actually give Black an advantage.

What about the French defense?

WhiteBlackFrench DefenseScoring %
1. e4e6French Tarrasch57.20%
1. e4e6French Steinitz57.10%
1. e4e6French Winawer55.80%
1. e4e6French Defense (All Lines)54.20%
1. e4e6French Advance50.00%
1. e4e6French Exchange46.00%***

This table helps explain shows that the Advance and the Exchange variations are not favorable for White. Given that these are choices the inexperienced player when confronted with the French Defense, it is understandable why so many feel uneasy against it. From the table, master strength and beyond are playing the White side of the Tarrash most successfully, garnering the most points there.

What about the Pirc, the Scandinavian, and the Caro-Kann?

WhiteBlackPircScoring %
1. e4d6Pirc54.90%
WhiteBlackScandinavianScoring %
1. e4d5Scandinavian56.40%
WhiteBlackCaro-KannScoring %
1. e4c5Caro -Kann Panov Attack55.20%
1. e4c5Caro -Kann 2 Knights54.60%
1. e4c5Caro-Kann Advance54.40%
1. e4c5Caro-Kann53.00%

None of these seem to be inspiring. The Fantasy variation gives White a scoring percentage at or around 56.0%.

Now for the Alekhine Defense. Unlike the Sicilian the Alekhine is less popular and below master strength, one would expect Black to score better than the table. There has been a faor amount of 2.e5 analysis that has yet to find its way into practice, so probably, this line will head in alignment. The only reason the Alekhine overall has a scoring percentage of 53% is that the e5 line has been played more frequently. Every other line shows White scoring less than 50%.

WhiteBlackAlekhine DefenseScoring %
1. e4Nf6Alekhine Defense (2.e5)55.00%
1. e4Nf6Alekhine Defense (All Lines)53.00%
1. e4Nc3Alekhine Defense47.50%***

Where does this lead us. The Practical choice for a response to e4 is the Alekhine defense. It will set the tournament player in a position that the amount of theory he will have to remember is greatly reduced, and it scores overall well. It will be important to look over the games of Lev Alburt and other practitioners of this defense to stay atop theory. Next, Let’s look at 1.d4.

Queen Pawn Openings
All Opening LinesScoring %
1.d41.d5Queen’s Gambit Declined58.60%
1.d41.d5Queen’s Gambit Accepted57.90%
1.d41.f5Dutch Defense54.00%
1.d41.Nf6Grunfeld Defense Exchange53.90%
1.d41.d5Nimzo Indian Defense52.00%
1.d41.Nf6King’s Indian Defense 6.. Na648.80%***

Overall, White Scores at 54.7%. White scores better than the Sicilian Defense. Although not listed. The Chigorin Defense and the Budapest Defense boteh score at 56% for White. Black’s best try is either the Nimzo- Indian , or to play 6…Na6 in all lines of possible. The KID 6..Na6 lines have produced a winning percentage of under 50% for White, meaning black has the edge in this line. White has an edge in the Smyslov line (58.0%) and an advantage in the e4 lines.

While the Dutch is a better choice that the QGD, so is the Grunfeld. The Grunfeld is very tricky and sharp and gives one’s opponents many chances to go wrong.

The Nimzo-Indian gives the best percentage changes for Black and woukd be the recommended choice on that basis.

So if we are to build a repertoire on the scoring percentages from 2020, the recommendation might look like this. First, play 1.d4 as White as it excludes the possibility to get the better and more fruitful positions of the Sicilian defense that give away around 2 wins per hundred games played to Black. Against 1.. e4, Black should play the Alekhine Defense as the win percentage is favorable to Black and few White players know it well. Finally, in response to1..d4 the conductor of the black pieces should play the Nimzo-Indian Defense as it gives Black the best winning chances.

I found this approach to opening selection interesting. I hope you did as well.

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