Study the opening tree you already walk
Most opening study starts at move one of a line you never reach. The cheap tree is the one in your own Chess.com or Lichess games.
Write down the first position where your games split. Everything before that is already decided. Study the split, not a course that never arrives there.
Export the forks first
Replay the last 80–200 standard games of one colour. Stop at the first decision you actually face more than once. That is the repertoire question.
Chessigma lists those most-played lines. Use them as the syllabus. Download someone else’s file only after you know which of their positions you touch.
Replace one move
If the Italian is your main line and one queen move is the leak, you need a replacement at that fork and a few model games. You do not need a new opening name.
Frequently asked questions
Should I copy a titled repertoire?
Only after you know you reach their positions. Their move 12 is useless if you are out on move 8.
Do I need an engine to pick the tree?
Not to choose which positions to study.
Chessigma imports public Chess.com and Lichess history and reports repeated choices — not engine grades. Import your games · Methodology