How does one really learn opening theory?

With due respect, Marin's repertoire book series on the English (published by Aagard's Quality Chess) are miles ahead than the best book Watson ever achieved.

But that is a book series, not one book on the English. Sure, a person can purchase a multi-volume set on one opening, but I don't think that is what the OP is after, reading his first post. I guess it depends on your skill level and how much information you want.

For me, one book on the English is plenty, and I happen to like John Watson's writing style. I am not an International Master!

I would argue that the ambitious player should puchase Marin and Watson if he wants to play the English!

Marin's rep book is limited to the 1.c4/2. g3 move order -- notably to avoid any possible transpositions into the Hedgehog formation (which Marin loves as black by the way). Watson doesn't cover every possibility in his volumes -- Musikmole describes quite well JW's intention with the 4 volume series -- but he does look at the 1.c4 and then 2. Nf3 and 2. Nc3 options, which can give rise to variations/systems not covered by Marin.

Incidentally, there is an old piece of advice which I first saw mentioned by Kotov in "Think Like a Grandmaster", although he probably isn't its originator. It is: study/learn a few systems in great depth whilst having a general knowledge of all the openings. Even if one never plays the Benko Gambit with White or Black, for example, it will enrich one's knowledge of chess to be aware of the typical ideas of the Benko. Did you know for example that Black, even though a pawn down, often can afford a queen exchange because it increases his positional pressure for the gambitted pawn? (It's a big surprise when you see that idea for the first time.)

I was adviced not to take up the Sicilian at my rating level, because these moves black makes - I cannot understand them either.

I've wanted to ask the same question.. I think most people are.missing the point to the question: we want to know how a certain opening works because it will, say, cause black to get slowed down, or it plays  on one side of the boards, or the aim is to take down thier white bishop, cause a slow blocked game of locked pawns, or removes their opportunity to castle, or is heavily attacking or defensive, or moves quickly to the endgame or cause hanging  pawns or isolated or will likely lead to an exchange of queens or material etc..I want a kind of description  so I can superficially at this point get a vision of how it's to be played and why, rather than hearing minutea like exd4 is awesome compared to a swebgian 3.. n6..the double flamingo  attack always  works well against a Sicilian..we don't know these things. We do know that a move will protect a certain square, make an opening, force the opponent to move, and these things are relatively obvious  to examine regarding just the next move.but I think what the poster is asking for is  a long term description of why one over the other, because they all look relatively the same, and the 3 opening moves that are always typically given show a board that doesn't scream obviously where and how a certain play should go..yes, know we could get a book on the history of the English opening and 1000 variations of it, were seeking more of a topographical comparison at rhis point  of how they play out so as to get inspired and insight to where a certain game will go.. and yes I can get a book and examine moves, I already do, but thats not the kind of description were after. Perhaps more of an analogy to American football with various plays where we could know that one play is more of a running game, or a kick, or long pass etc.. cause after the first 3 moves for amateurs they all look much the same, generally speaking.. when I go to the second hand book shop and look for chess, it's either books for children, or a 50s text printed with old ink and wonky typesetting and boasts about having 10,000 games to study for your enjoyment.! Ah no, we need  at this point in our thinking more descriptors of the type of play and what it will lead to ( not just check) to have sort and assimilate the material. With 1000 openings and 1000 variations on each, classifications on types of openings is saught. All the  books give 3 moves for 1000 openings, or 1000 moves for a given opening.. I don't expect anyone to really have the answer, because after a few months of study I don't see the obvious answer and I can only assume the majority of  players are not asking this. I guess the question is more specifically are there descriptors of what kind of middle and end game typically develops  is arrived at from a given opening, rather than hearing black wins 37% of the time with a nimzo..I can play 3 moves, but I dont want to study 100 variations on one opening just now.we will, in time, do that, but at the moment want an overview of why a certain game..ie if one plays one opening what to proceed with against..and also, if they give a variation, does one stick to the formula against it because it's the strongest, or develop a variation also..just a comparison of openings and reasoning.  Saying that one opening blocks f3 and another opens column 4 doesn't mean much to a beginner..I know what those terms mean technically, but that's typically going from oh these two beginner moves, and here's the grandmaster outcome..the middle ground needs laying out as to why and wherefores..thanks. this is also more for general classification so as to make a plan of how to study and knowing why I'm studying a certain set of moves..they all say develop centre castle early..and then just the move details..billions of them. Seems a lot of education material is dummies books or be like the grandmaster.. surely someone has classified the openings into types by now? I think thats what were really asking.. types of openings and what kind of middle and endgame does it procure, to make light reading and enjoyable perusal, and to whet the appetite to study knowing what to go for..thanks 

It sounds like the question here is regarding the “why” of the earliest moves played in a given opening, say before move 6.

Most opening books don’t start explaining much until later, after a characteristic tabiya is reached. Usually by then, a novice game will have veered elsewhere ... this has certainly happened more in my OTB experience (against sub-1400 level players) than online, where folks use opening databases and books (which is partly why I quit playing online chess games).

The explanations of the really early moves would ideally have to cover an insane amount of ground, and therefore likely will not be to the satisfaction of the very analytically-inclined, obsessive-compulsive, burning-to-not-lose-before-move-7, but rather unskilled, novice player.