“Play the opening like a book, the middlegame like a magician, and the endgame like a machine.” – Rudolph Spielmann
In chess, the opening is the initial sequence of moves. While the game presents a very large number of possibilities (see the Shannon number), optimal starting moves are being studies for a very long time. Games are often annotated using the Encyclopaedia of Chess Openings classification system. Each standard opening has its own ECO code which helps classification of games and improves searcheability for later analysis.