Developing move

At the start of a game, most pieces are confined behind their pawns. A developing move usually brings a knight or bishop off its starting square and places it where it controls useful squares, defends something important, or helps create a threat. Development is not merely moving a piece. It is making that piece take part in the game.

Good developing moves often serve several purposes at once: fighting for the center, helping the king castle early, and improving coordination. Knights and bishops usually come first because they can become active immediately, while rooks normally need other pieces to clear their paths.

A pawn move may open a diagonal for a bishop or queen, but it is not usually counted as developing a piece. Moving the same piece several times also adds no new development. It may spend moves that the opponent uses to activate the rest of the army and obtain a lead in development. There are valid exceptions: escaping an attack, winning material, or creating a concrete threat can justify moving a developed piece again.