Opening repertoire

A White repertoire starts with one or more first-move systems and prepares answers to Black's major replies. A Black repertoire needs an answer to the main White first moves, usually organized separately against 1.e4, 1.d4, and other starts.

A repertoire fails when it contains a deep main line but no answer to an early common deviation. Begin with a playable response to each frequent branch, then deepen the lines that actually recur.

Move sequences are easier to maintain when they lead to pawn structures and plans you recognize. Two lines that look different in notation may belong together when they transpose to the same position.