Opening theory in chess 1. e4 e5

Black plays the classical response to 1. e4. By mirroring White's move Black has guaranteed himself an equal share of the centre and scope to develop his pieces. 1...e5 is one of the few moves that directly interfere with White's plan of playing d4. But the move's merit is also its drawback; with the position once again symmetrical, White to move has the initiative and sooner or later will be able to break the symmetry to his own advantage. The pawn on e5 is undefended and it is easy for White to develop in a way that restricts Black's possible responses, by simply threatening to capture it. Though the move is still common at every level, it has seen a modest decline in popularity during the 20th century for these reasons.

The classical move for White is 2. Nf3, threatening Black's undefended pawn while developing one of his kingside pieces in preparation for castling. Another plan is to open the f-file for an attack on Black's weak f7 point, an idea which underlies a trio of related moves the variations of which frequently transpose into each other: 2. f4, 2. Nc3 and 2. Bc4.

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Opening theory in chess 1. e4

White's aggressive opening move opens lines for the queen and king's bishop and fights for control of the squares d5 and f5. 1. e4 is the most traditional of White's first moves, is popular at all levels of the game and in recent times was the favoured opening move of world champions Bobby Fischer and Anatoly Karpov, Fischer calling it 'best by test'. Openings with 1. e4 tend to emphasise violent tactics over slow maneuvering.

At this point Black must decide how to face White's aggression. With a pawn on e4 White's simplest plan is to play d4 on the next move, giving himself a strong 'classical' centre, so the most aggressive replies by Black are those which challenge White's control of d4. 1...e5 challenges it directly, establishing an equal share of the centre though allowing White to maintain for longer the initiative conferred by having the first move. 1...c5 creates an unbalanced position of attack and counter-attack and is the more popular move. 1...Nc6 is playable but does not prevent d4 since the knight cannot take the pawn.

Alternatively, Black may challenge White's central control by targeting the newly arrived e4 pawn, either with 1...d5, with a likely exchange of central pawns leading to a wide-open game in which minor piece placement is crucial, or with 1...Nf6 inviting White to build a large centre which may later be attacked. 1...f5 is a poor move since the attacking pawn is en prise.

Other first moves by Black allow White to place pawns on e4 and d4, usually in the hope of locking the centre pawns in place and fighting for supremacy on the flanks. 1...e6 is by far the most popular of such moves; along with its cousin 1...c6 it fights for control of the important d5 square. 1...d6 and 1...g6 are related moves - where one is played, the other usually follows soon - aimed at setting up a particular defensive formation called the King's Indian which has been widely studied. 1...b6 is occasionally played but allows White to attack quickly, and while the late English GM Tony Miles beat Anatoly Karpov in a famous game with 1...a6, it neglects the centre and is not recommended to anyone less skilled than Tony Miles.

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