Cracking the Chess Code: A Groundbreaking Study Reveals Hidden Patterns in Openings

Using real data from an online chess platform, scientists of the Complexity Science Hub and the Centro Ricerche Enrico Fermi (CREF) studied similarities of different chess openings. Based on these similarities, they developed a new classification method that can complement the standard classification.

“To find out how similar chess openings actually are to each other – meaning in real game behavior – we drew on the wisdom of the crowd,” Giordano De Marzo of the Complexity Science Hub and the Centro Ricerche Enrico Fermi (CREF) explains. The researchers analyzed 3,746,135 chess games, 18,253 players, and 988 different openings from the chess platform Lichess and observed who plays which opening games.


If several players choose two specific opening games over and over again, it stands to reason that they will be similar. Opening games that are so popular that they occur together with most others were excluded. “We also only included players in our analyses that had a rating above 2,000 on the platform Lichess. Total novices could randomly play any opening games, which would skew our analyses,” explains Vito D.P. Servedio of the Complexity Science Hub.

Ten Clusters Clearly Delineated

In this way, the researchers found that certain opening games group together. Ten different clusters clearly stood out according to actual similarities in playing behavior. “And these clusters don’t necessarily coincide with the common classification of chess openings,” says De Marzo.