chess opening

Classification of chess openings
[edit]
For a list of openings as classified by the Encyclopaedia of Chess Openings, see List of chess openings.
Chess openings are primarily categorized by move sequences.[19] In the initial position, White has twenty legal moves.[20] Of these, 1.e4, 1.d4, 1.Nf3, and 1.c4 are by far the most popular as these moves do the most to promote rapid development and control of the center. A few other opening moves are considered reasonable but less consistent with opening principles than the four most popular moves. The Dunst Opening, 1.Nc3, develops a knight to a good square, but is somewhat inflexible because it blocks White's c-pawn; also, after 1...d5 the knight is liable to be driven to an inferior square by ...d4. (Note that after 1.Nf3 the analogous 1...e5? loses a pawn.) Bird's Opening, 1.f4, addresses center control but not development and weakens the king position slightly. The Sokolsky Opening 1.b4 and the King's and Queen's fianchettos: Larsen's Opening 1.b3 and 1.g3 aid development a bit, but they only address center control peripherally and are slower than the more popular openings. The eleven remaining possibilities are rarely played at the top levels of chess. Of these, the best are merely slow such as 1.c3, 1.d3, and 1.e3. Worse possibilities either ignore the center and development such as 1.a3, weaken White's position (for instance, 1.f3 and 1.g4), or place the knights on poor squares (1.Na3 and 1.Nh3).

Black has twenty complementary responses to White's opening move.[20] Many of these are mirror images of the most popular first moves for White, but with one less tempo. Defenses beginning with 1...c6 and 1...e6, often followed by the center thrust 2...d5, are also popular. Defenses with an early ...d6 coupled with a kingside fianchetto are also commonly played.

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. Since these categories are still individually very large, it is common to divide each of them further. One reasonable way to group the openings is:

Double king pawn, symmetric or open games (1.e4 e5)[21]
Single king pawn or semi-open games (1.e4 other)
Double queen pawn or closed games (1.d4 d5)
Single queen pawn or semi-closed games (1.d4 other)
Flank openings (including 1.c4, 1.Nf3, 1.f4, and others)
Unusual first moves for White
The Indian systems (1.d4 Nf6) are the most important[22] of the semi-closed games, and warrant separate treatment.

if you like my blog please join my club https://www.chess.com/club/chess-legends-94/join