It is important to have a repertoire suited to your skills and your style of play. What matters is how much you feel at ease, and how well you know it. Check out the books below to build your own repertoire.
The three books illustrate the explanation behind the theory while the games are examples of the topic dealt with. Check out the books below to learn chess strategy.
It is known that strong players, thanks to the accumulated experience, see the chessboard as a group of elementary groups (or chunks), known as structure and characteristic. The increase of knowledge in known and assimilated patterns will vastly improve a players game play.