“Chess is a terrible game. If you have no center, your opponent has a freer position. If you do have a center, then you really have something to worry about.”
(Seigbert Tarrasch)
Openings are partly about controlling as much space of the centre as possible directly or indirectly. The centre is one of the most important resource on the board, it is a quasi “high-ground”. Why? Look at the light pieces (the bishop and the knight), to understand the reason:
If one wants to maximise the number of squares controlled by a light piece then one shall place them on one of the squares marked by green. Outside the green zone, the number where these pieces can move to is decreasing. Note that, we used the terms “moving to” and “capture” as synonyms since for these pieces the rule to capture and to move is the same. The wider green zone (the knight’s green zone) is called the wide centre, and the bishop’s green zone is called “the centre”.
There is a piece on the board for which these two (I mean moving to and capturing) are always different. Yes, for pawns they are very different. Pawns can control up to two squares (one square diagonally ahead), but they can advance forward straight ahead only one. Well, except for their first move. Pawns are formidable opponents when it comes to defending a position, and that is why many players really try to control the centre by pawns. Following that logic, we find that in rook endings, the importance of the centre decreases at some extent. Do not get me wrong they are still important because the king is closer to every square from there (up to 4 moves). But in a rook ending the centre is not as important as at the beginning of the game since rooks can oversee 14 squares from every position if they are not blocked. But let’s get back to centre.
How one can control a square SQ on the board? Technically, one can do that by either occupying it with a piece (if we do not lose the aforementioned piece), or by positioning more pieces on squares from where they can capture pieces on SQ. If there is an equilibrium in the number of pieces than it is also important to realise the total value of the pieces determines the winner for a very good reason: if one can sacrifice less to achieve a goal then in the long run that side will most likely win. For instance, if one exchanges piece with “nominal” value of 3 (knight or bishop) for a piece with value of 5 (rook) then the side who sacrificed the lower value will win. Look at the following position:
The square d5 marked with blue is controlled by the same number of pieces: by a pawn on e4, and by the knight on f6. However, the pawn has lower nominal value, so we can say that d5 is controlled by White. On the other hand, while e4 (marked with red) is occupied by White, but that piece is undefended. So the knight on f6 effectively controls single-handedly the e4 square at the moment. Let’s see these ideas in practice.
This little game snippet shows what Tarrasch felt about the centre (see the quote at the beginning of the article). It is an advantage and a burden to keep it intact. Even a slightest mistake can ruin everything because if the centre is lost, the game is lost, too.