Add an option in study mode to emphasize studying "difficult" lines (spaced repetition)

[GoodChessMind]

Indicates on website that training is done by the program that randomly selects your opponents reply. Would be great if the program picked a reply by your opponent based on a smart selection, which would be based on the percentage you got the variation correct and incorrect.

[jven]

This is similar to what Chessable does, using some sort of spaced repetition (https://en.wikipedia.org/wiki/Spaced_repetition).

For now this isn't at all possible since we don't store any statistics from study mode, but something to consider for the future.

[jven]

Another request from different user: "Implement some sort of spaced repetition algorithm. I know chessable does it but they didn't invent it. I think Anki uses open source programming, and their spaced repetition algorithms are excellent. It'd be a very appealing feature!"

[vitogit]

For spaced repetition there is this project https://github.com/ArneVogel/listudy Not sure if you can get some idea