How to memorize opening lines effectively? (without buying memberships)

@yangtuo said ^

I find that most of the online interactive chess opening courses are quite expensive(except free studies in Lichess)

Build yourself a repertoire...

how many lines do you have in your repertoire ? tools like chessbook or chessatlas allow 200 lines of variations for free which is way enough for < 2300 elo repertoire

"... Overall, I would advise most players to stick to a fairly limited range of openings, and not to worry about learning too much by heart. ... the average player only needs to know a limited amount about the openings he plays. Providing he understands the main aims of the opening, a few typical plans and a handful of basic variations, that is enough. ..." - 101 Chess Questions Answered (2008) by FM Steve Giddins

'I didn't know so well chess theory, the theory of chess openings.
And so, of course I knew the theory, but not on the level of the best players, so this was always my weakness.' - Karpov

@tpr said ^

'I didn't know so well chess theory, the theory of chess openings.
And so, of course I knew the theory, but not on the level of the best players, so this was always my weakness.' - Karpov

If I remember correctly, Reshevsky was famous for no recalling opening theory [and making a lot of errors in the opening] but also for never missing anything 3 moves deep.

"Reshevsky was famous for no recalling opening theory"

• Spassky too. In the 6th match game against Fischer in 1972 he forgot 14...Qb7 as Geller had shown him and played the mistake 14...a6? instead.

In response to a different forum post, I mentioned that I have a copy of Modern Chess Openings, 15th edition...well, aside from using it as an occasional reference, I should probably shelve the book. If I remember correctly, the book is 18 years old. The book is not 100% useless, but it is certainly outdated in the chess world. I need to find a new source for my openings...not so I can memorize openings, but so I can correct some mistakes in my game. I don't use an up-to-date database, as it is a bit expensive. I learn chess better in hands-on situations, so I guess I could go to the chess club more often and ask some rated Experts to go over my games. The worst they can do is say no...

Practical Chess Openings (2025) by GM Martyn Kravtsiv
http://www.gambitbooks.com/pdfs/PCO_Practical_Chess_Openings.pdf

There's a fairly simple way to remember openings.

You don't memorise moves, you memorise plans. Then what you do is you remember what plan to use against various opposing move orders.

This has two benefits

1. You can use same play against several opposing lines. So rather than remember long lines you can reapply same line.
2. If your opponent deviates you have two approaches. Either stick to the original plan or transpose to another plan.

@kindaspongey Thanks for the name of the book. I hope I can get a copy soon.