How will knowing all 500 ECO codes improve your skills as a chess player? Do you plan on playing every opening out there or focus on positions that you understand and enjoy playing?
ECO Code (A00-E99)

Let’s take 1.e4 e5 2.Nf3 Nc6 3.Bb5 for example. This can be called the Ruy Lopez or the Spanish Opening. And it has even more names in other languages. How to refer to a variation of a Ruy Lopez in a way everyone understands? With codes, of course.
So “knowing all the 500 ECO lines” essentially means knowing 500 names.

I was talking about actual codes instead of just the names since most materials on opening available around are classified on these. It's understandable that it's just a classification, but the question is whether this particular classification is worth memorising.


The Wikipedia says that it's important for serious players to master it.
The classification is totally arbitrary but given the effort put by many based on it, I feel that it will give a systematic approach to the opening and give you a sense of confidence as to where you are going with the moves.

The Wikipedia says that it's important for serious players to master it.
This illustrates the principle that any idiot can post into the Wikipedia.
Memorizing ECO codes isn't chess... it's "stamp collecting".
If you want to cross-reference opening lines to ECO codes, don't needlessly kill brain-cells memorizing the codes. Just *favorite* a website like 365chess, which will automatically give you the code for any sequence of moves that you enter into the Opening Explorer.
That way you can translate from move sequences to ECO codes as you need them.
How important is it to know all the 500 ECO lines for someone who is serious about chess?