Comparison with other tools

Here's a quick high-level overview of Chessbook vs other opening study software.

The short version is that Chessbook is built around the idea that an opening repertoire should be measurable. It should be clear what you've covered, what you're missing, how well you know it, and whether the repertoire itself is any good.

Lichess studies are excellent for writing analysis and sharing lines, but they don't really tell you what your repertoire is missing or when to review each move.

Listudy and Chesstempo are closer to opening trainers. They can help you drill lines, but Chessbook is more opinionated about repertoire coverage, spaced repetition, and stats like Effectiveness, Soundness, and Learnability.

A private Chessable course can be great if you already have exactly the course you want. Chessbook is more useful when you're building or maintaining your own repertoire, importing multiple sources, or trying to understand the gaps and tradeoffs in what you play.

None of this means you shouldn't use the other tools. They're good at different things. Chessbook is for keeping your repertoire alive: finding gaps, practicing the right moves, and making the repertoire easier to reason about.