Common aims in opening in chess

Irrespective of whether they are trying to gain the upper hand as White and equalize as Black or to create dynamic imbalances, players generally devote a lot of attention in the opening stages to:

1. Development: One of the main aims of the opening is to mobilize the pieces on useful squares where they will have impact on the game. To this end, knights are usually developed to f3, c3, f6 and c6 (or sometimes e2, d2, e7 or d7), and both player's King and Queen pawns are moved so the bishops can be developed (alternatively, the bishops may be fianchettoed with a manoeuvre such as g3 and Bg2). Rapid mobilization is the key. The queen, and to a lesser extent the rooks, are not usually played to a central position until later in the game, when many minor pieces and pawns are no longer present.

2. Control of the center: At the start of the game, it is not clear on which part of the board the pieces will be needed. However, 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. The classical view is that central control is best effected by placing pawns there, ideally establishing pawns on d4 and e4 (or d5 and e5 for Black). However, the hypermodern school showed that it was not always necessary or even desirable to occupy the center in this way, and that too broad a pawn front could be attacked and destroyed, leaving its architect vulnerable; an impressive looking pawn center is worth little unless it can be maintained. The hypermoderns instead advocated controlling the center from a distance with pieces, breaking down one's opponent center, and only taking over the center oneself later in the game. This leads to openings such as Alekhine's Defense - in a line like 1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. c4 Nb6 5. f4 (the Four Pawns Attack), White has a formidable pawn center for the moment, but Black hopes to undermine it later in the game, leaving White's position exposed.

3. King safety: The king is somewhat exposed in the middle of the board. Measures must be taken to reduce his vulnerability. It is therefore common for both players to either castle in the opening (simultaneously developing one of the rooks) or to otherwise bring the king to the side of the board via artificial castling.

4. Prevention of pawn weakness: Most openings strive to avoid the creation of pawn weaknesses such as isolated, doubled and backward pawns, pawn islands, etc. Some openings sacrifice endgame considerations for a quick attack on the opponent's position. Some unbalanced openings for black, in particular, make use of this idea; such as the Dutch, and the Sicilian. Other openings, such as the Alekhine and the Benoni, invite the opponent to overextend and form pawn weaknesses. Specific openings accept pawn weaknesses in exchange for compensation in the form of dynamic play. (See pawn structure.)

5. Piece coordination: As each player mobilizes his or her pieces, each attempts to assure that they are working harmoniously towards the control of key squares.

6. Create positions in which the player is more comfortable than the opponent: Transposition is one common way of doing this.

 Apart from these ideas, other strategies used in the middlegame may also be carried out in the opening. These include preparing pawn breaks to create counterplay, creating weaknesses in the opponent's pawn structure, seizing control of key squares, making favourable exchanges of minor pieces (e.g. gaining the bishop pair), or gaining a space advantage, whether in the centre or on the flanks.