Here's a question (by email) from Brett Thomas-DeJongh:
For example, when I listen to chess.fm live broadcasts I sometimes hear things like, "Well, we'll leave that up to the theoreticians." I always thought that the people who make the theory are the Super-GMs trotting out the novelties in top tournaments. We hear about Bobby Fischer being a theoretician of the King's Indian, Geller revolutionizing it, etc. Also, when we hear that Topalov played Nxf7 in the Moscow variation against Kramnik, Cheparinov had analyzed this sacrifice to move 40.
Are there other theoreticians besides the top OTB players? Are top correspondence players the real theoreticians? And last, are there any theoreticians who are not above a certain ELO, say 2600?
We should distinguish between theory and theoreticians. Theory is the product of all chess players' work. It's not only the games of super- or even regular GMs that count, but those of any competent players (both OTB and correspondence) whose games reach the databases, that define a certain position as "theory". That's probably the most general sense. In a more specialized sense, "theory" is what gets written about by "theoreticians", and in this case it's generally NOT the super-GMs who count. Who are the theoreticians? Here's the answer. Do you have an opening book? Look at the front cover. If you see a name on it, then congratulations: you've just identified one!
That's really all there is to it. If someone writes an opening book, then presto! - he or she is a theoretician. Likewise if someone writes an article on an opening in a magazine or journal, or discusses an opening in an online source (even in a blog, for instance). There's really nothing more mysterious than that. In fact, it's generally not GMs who are considered "theoreticians", even if it's their games that are most prominent in pushing theory along. It's generally the scribblers a few notches lower, whose main claim to fame is their writing on openings, who get that moniker. (Examples: Richard Palliser, a 2406 FIDE player who seems to publish a new opening book every week; and in the avant-garde department, Stefan Bücker, a German FM known for his development and advocacy of some mighty peculiar-looking ideas and his editorship of Kaissiber.)
Bernard: Maybe John Watson or Edward Winter could answer the history of terminology question. The general association of "theory" with opening theory doesn't seem that surprising to me though, as opening theory dwarfs middlegame and endgame theory in size and activity. I have seen the phrase "endgame theory" though, and people like Yuri Averbakh have been referred to as endgame theoreticians. So I think "theory" is an abbreviation for "opening theory".
I disagree that writing an opening book makes you a theoretician. John Watson's work on the French went far beyond catagorizing the different variations. He brought insights that gave players a better understanding of the opening.
Some practicing super GM's are theoreticians in that their new moves go beyond a new tactical turn, they often find new strategies as well. Kasparov comes to mind as he launched many new approaches to standard openings.
Very nice blog, btw.
Pachman and others have written a lot a lot about planning, but perhaps there is a distinction between those who broke new ground and those who just collected previous knowledge, much like the distinction Mikolov above made where he doesn't consider Watson an opening theoretician, at least with regard to his work on the French Defense book, because he only collected the work of others.
I disagree with you about middlegame theoreticians, but we have to distinguish two types. First, there are those who are writing instructional books, and there it's largely a matter of moving the furniture around rather than creating something new. Not much is happening there. But there's a second type, and here there's plenty of activity. This sort is typically subsumed under opening theory, though - it occurs in the deep investigation of openings and pawn structures, and is quite vibrant. See Ivan Sokolov's new book Winning Chess Middlegames for a terrific example of this genre.
How about Nimzovich, though? He came up with new observations on pawn structures and over-protection that were largely realized in the Middlegame, although they were also seen in Opening theory.
How about Kmoch? He certainly came up with a lot of "theory" in Pawn Power In Chess, although of questionable value perhaps.
About your first point, I'm not aware of any such player. Some people have more to say that's new, some less, and not all contributions are equal. But even bad players writing about openings aim to go beyond merely collecting what's been done already.