Maybe to give advise, it is crucial to know that my real life rating is 1900. Here on chess.com it is much lower, because it is only based on 1 game right now, I'm new here :).
KID (Kings Indian Defence)

Kotronias' books are better suited for KID experts, taking the study to the next step beyond ideas/structures and to concrete variations. So I won't recommend those especially since it's a Grandmaster Repertoire and not a book that covers (almost) everything.
Bologan's book is pretty good, arguably the best for the newest KID players, however he tends to prefer Benoni structures where you might want to play something more KID like.
Vigorito's books are decent too, a lot of variations too but not always too deep and multiple options against various White's setups (as opposed to Grandmaster Repertoire).
Video's are my personal favorite to learn, but that's different for every individual. I like to combine grandmaster games by books, as in just going carefully through the games entirely in the books.
Hello everyone,
After years of just playing different kind of openings against 1.d4 (and 2.c4), I really want to focus on one opening with black against 1. d4 and 2. c4.
Now I finally know what I want to play, the KID (better known as the Kings Indian Defence).
My question is: how can I master this opening the best? Books (what books?), videos, or just by looking at grandmaster games or something else?
I don't want to just learn the main lines and sub variants, I ofcourse also want to know the ideas behind etc.
Kind regards,
Gertjan