Opening

A chess opening is the group of initial moves of a game (the "opening moves"). Recognized sequences of opening moves are referred to as openings or defenses, and have been given names such as the Ruy Lopez or Sicilian Defense, and are catalogued in reference works such as the Encyclopedia of Chess Openings. There are dozens of different openings, varying widely in character from quiet positional play (e.g. the Réti Opening) to wild tactical play (e.g. the Latvian Gambit). In some opening lines, the moves considered best for both sides have been worked out to 30-35 moves or more. Professional players spend years studying openings, and continue doing so throughout their careers, as opening theory continues to evolve.

Although a variety of moves can be played in the opening, the fundamental strategical aims are similar:^[38]

• Development: To place (develop) the pieces on useful squares where they will have an impact on the game. For example, knights are often developed to f3, c3, f6 and c6 (or sometimes e2, d2, e7 or d7).
• Control of the center: Control of the central squares allows pieces to be moved to any part of the board relatively easily, and can also have a cramping effect on the opponent.
• King safety: enhanced via castling, for example.
• Pawn structure: Players strive to avoid the creation of pawn weaknesses such as isolated, doubled and backward pawns, and pawn islands.

Apart from these ideas, other strategic plans or tactical sequences may also appear in the opening