The
Encyclopedia of Chess Openings (or
ECO) is a classification system for the opening moves in
chess. It is presented as a five-volume book collection (now also a computer database) describing
chess openings. The moves were taken from hundreds of thousands of games between masters, from published analysis in the
Chess Informant since 1966, and then compiled by notable chess players. The main editor is
Aleksandar Matanovic. Both the ECO and the
Chess Informant are published by the
Serbian company Šahovski Informator (Chess Informant). These openings are typically provided in an
ECO table that concisely presents the best opening lines.