I Built a Tool to Stop Forgetting My Openings

The Real Problem with Opening Study

You memorize lines. You drill them. Then in a real game, you deviate on move 7.
The problem is not memory. It is feedback.
You rarely know which moves you keep forgetting.
So you cannot fix them.
Standard opening books do not tell you where you personally go wrong.
Your game history does.

A Workflow Based on Your Own Games

I built ChessAtlas to solve this.
The core idea: import your actual games, compare them against your repertoire, and see exactly where you went off-book.
Here is the workflow I use week to week.

Step 1: Build or Fork a Repertoire

You can build a repertoire from scratch using a PGN editor.
Or fork one from the library if you play a common opening.
The library currently has repertoires for the French, Caro-Kann, London, Italian, Sicilian Alapin, and Ruy Lopez.
Each one is a starting point you can edit freely after forking.

Step 2: Import Your Lichess Games

Connect your Lichess username and pull in your recent games.
The import runs in the background and works for both colors.
You can import from Chess.com as well.

Step 3: See Your Deviations

After the import, the app shows every game where you deviated from your repertoire, and on which move.
You get a list like:
- Game vs. player123: deviated on move 8 (you played Bc4, repertoire says Bb5)
- Game vs. player456: deviated on move 5 (you played d3, repertoire says d4)
Most players repeat the same 3 or 4 mistakes across dozens of games.
Seeing them in a list makes this obvious fast.

Step 4: Train the Moves You Keep Missing

Training uses spaced repetition (FSRS algorithm).
Moves you keep missing come up more often.
Moves you already know fade into the background.
After a few weeks of short daily sessions, the deviation list gets shorter.

What Actually Surprised Me

I expected the deviations to be scattered across many moves.
They were not.
I had one move I was getting wrong in the majority of my French Defense games.
Just one move, on move 6.
Drilling that specific position for a week fixed most of my opening problems in that line.
The import feature makes this kind of targeted fix possible.
Without it, I would have kept rereading the same opening books without knowing what to focus on.

Try It

ChessAtlas is at chessatlas.net
I am the developer, so take my recommendation with that in mind.
The import and deviation detection are free to use.
If you try it, I would be curious what your most common deviation turns out to be.
Feel free to share in the comments.