 The most important scheme of classifying chess openings for serious players is by ECO code, a series of 500 opening codes assigned by the "Encyclopaedia of Chess Openings".Although these codes are invaluable for the serious study of the chess opening, they are not very practical for a broad survey of the chess opening as the codes obscure common structural features between related openings.A simple descriptive categorization of the chess opening is King's Pawn Openings, Queen's Pawn Openings, and Others.