Learnability

Learnability is a repertoire statistic that estimates how easy your repertoire should be to remember.

This is different from Effectiveness and Soundness. A line can be effective and sound, but still hard to learn because the moves are rare, unnatural, inconsistent with nearby positions, or just easy to mix up.

To estimate this, Chessbook looks at the moves in your repertoire that count toward your coverage goal, then predicts how hard those moves are likely to be to learn. The model is trained on real review history — specifically, how often people got similar moves wrong in their early reviews.

Some of the things that matter:

• how common the position is
• how likely your move is in games at your level
• whether similar positions in your repertoire tend to have the same kind of answer
• how deep in the line the move appears

The result is then converted to a 1–99 score. The bottom of the scale is anchored to the hardest-to-learn repertoires you could plausibly end up with (built from real book moves in proportion to how often people play them), and the top to the most learnable repertoire Chessbook's auto-fill can construct for your rating, side, and coverage goal. See how the scores are scaled for details.

A low learnability score does not necessarily mean the repertoire is bad. Sharp openings, forcing tactical lines, and ambitious sidelines can all be harder to remember. The stat is meant to show the tradeoff, not make the decision for you.