Opening moves are just that - moves. Knowing their name doesn't necessarily give you power over them but may help you find them in a book, or talk about them afterwards! Like any other move there are ( or should be) ideas behind them. 1. e4 occupies the centre, attacks the squares d5 and f5 and allows the bishop and Queen into the game.

This is the first move of the Sicilian Defence. Black chooses an asymmetrical move that concentrates more on the dark squares in the centre. d4 is attacked but only the Queen has improved access to the game. Possible plans for further development include d6 Nc6 g6 and Bg7, or e6 and Be7. The Q may go to c7 or a5. The c pawn will normally exchange for white's d pawn leaving a 2-5 pawn set facing a 3-4 pawn set and a partly open c file for Black to potentially exploit.

White throws forward the d pawn thus ensuring neither bishop is hindered by pawns. The d pawn is supported by the Queen only and thus if exchanged the Queen will be dragged into the middle of the board where she could be attacked by moves such as Nc6 losing development time.

Black captures the pawn. At this stage a general rule is that a central pawn is of greater positional value than a flank pawn so this exchange is a marginal benefit to Black. This only matters when Black is skilled enough to come out of the opening without losing material to some tactical disaster. Very good players can bring these factors (see note to Blacks third move) under their control almost from the off but the rest of us survive the opening and then find we have some more possibilities available to us when we reach a middle game.

White refrains from bringing the Queen out early and attacks the pawn a second time with the Knight. Black cannot defend the pawn.

Black attacks the e pawn, now Nxd4 is answered by Nxe4 when White is a pawn down and Black has two central pawns which he can use to seize key central territory as the game progresses.

White moves the pawn out of the way of the attack and forces the black knight to move. This shows the difference between a symmetrical and asymmetrical opening - the central pawns have more options. Protecting e4 with either Bd3 or Nbd2 is more passive and the pieces begin to hinder each other.

The knight moves into the centre as going to h5 or g4 will require a further protective move after Nxd4 as the white Queen will attack it. Going back to g8 loses time. Another feature of this move is that now the d4 pawn is pinned.

This move attacks the pinned d4 pawn. If cxd4 white will have greater central occupation and a lead in development, as he can bring his pieces out with no further pawn moves. By a circuitous route we have reached a mainline position in something called the c3 Sicilian with Nf6. What matters is the tactical threats, the ideas, then perhaps the names.

One thing that always needs looking at is whether any pieces are unprotected and what functions are being undertaken by each piece or pawn. The pawn on d4 has taken on the role of protecting the knight on d5 from an attack by White's queen, thus a move to protect the knight with e6 or moving it out of the line of fire to b6 made more sense than this self discovered attack.