I wanted to suggest a possible new opening training for lichess that's different than chessable, chess position trainer, and bookup. All these programs are quite nice but I thought about a different kind of opening trainer. What these programs have in common is that they train you in your repertoire. The downside is that when you play a move that is not your repertoire it will automatically count that as incorrect, which can be daunting.
The new kind of opening trainer I propose is one that tests you based on the opening name. The opening trainer would give you the most specific name of the opening and the ECO code and you would have to play that for both sides. For example, the opening trainer would say: "play the schliemann defense ECO code C63". You would have to play the following moves for both sides in the trainer to get it correct: 1.e4 e5 2.Nf3 Nc6 3.Bb5 f5.
There is one issue with this and that is how many ply do you go to before you tell the trainer to stop with the opening. Scid vs PC subcategorizes the opening for the schliemann defense based on letters. For example C63a, C63b, etc...I was thinking that you would have to subcategorize the opening for the schliemann defense based on the ECO code to make the variations work for a certain ply. The only issue is that there are too many variations that can be played and subcategorization may not be enough to make the trainer work if you want to go for example 15 moves or 20 moves deep because you don't know the VERY specific name of the opening at that point. For example, the opening trainer could tell you to play C63d of the schliemann defense and based on what scid vs pc shows that it is only 4 moves deep which is: 1.e4 e5 2.Nf3 Nc6 3.Bb5 f5 4.d3 . The key that subcategorizes the schliemann defense is based on the d part of c63 and the key move is d3 for white. So basically my issue is that the depth for specific variations would not go that far in the opening unless there is a better way to subcategorize the opening.
The purpose of this opening trainer is to learn openings generally instead of having to make a repertoire. If anybody has any further ideas about this opening trainer please let me know.