the aim of the opening phase to move pieces from their initial to more advantageous squares to occupy or control the center to gain more space and more attack and defense possibilities, or activity, as well in hindering the opponent from doing so. In the first place this applies to the minor pieces, knights and bishops, in conjunction with the required pawn moves to open lines aka diagonals to mobilize bishops.
Each development of a minor piece, and finally connecting the rooks on the base rank due to castling, is considered a tempo, but no pawn move. In tempo sensitive, often dynamic and tactical opening lines with early pawn levers and options to open attacking lines, Tarrasch rates three tempi worth about the value of one pawn , which is the motivation of many gambit openings.
A rule of thumb is not only to avoid premature pawn moves, but also moving the same piece multiple times without a good reason, and to develop most or at best all minor pieces before starting attacks with the queen - since too early queen development without appropriate support makes her vulnerable to opponent piece attacks, often worsening the tempo balance if not worse.
While some programs rely on the opening book and appropriate piece-square tables as well as mobility and center control terms to encourage piece development, others have explicit terms for this early game phase and consider a tempo balance and extra penalties for knights and bishops on their initial home squares. Quite common is also to punish blocked center pawns on their base rank, and too early development of the queen.
- Center Control
- Opening Book
- Piece-Square Tables
- Returning Bishop
- Chess Strategy/Development - Wikibooks
- Glossary of chess - Develop - Wikipedia
- Chess Opening Tutorial : Count the Developing Moves from Chess for All Ages by Mark Weeds