Should I Know More Than One Opening?

do you KNOW how many less chess forum fights will happen now!!?

I don't know guys I think chess.com lost real cash with this banning.  I rate chess.com stock as a strong "sell"

get your money back before you got nothing.

as for me, I guess I will go back to my quiet blog.  there's not going to much talk around here any more.

So earlier today when I was driving back from my piano lesson (yes, I have a license, and of course I probably shouldn't be vizualizing chess positions while driving but I couldn't avoid it lol) I was thinking about the position where McCartney could have played Nd2 and I remembered that he and Fiveofswords were analyzing the move Rd8 but I started thinking about what happens after Nd3...so I calculated (in my head, remembering the position) the following line but clearly it's winning for white:

I guess that line doesn't work either, so Nd2 must be winning there. 

The main reason I wanted to post this I guess was that I wanted to check when I got home that all my blindfold analysis was correct- I've only recently been learning blindfold and practicing vizualization (so I was happy to have analyzed correctly)...and it further shows that Nd2 was winning. For the record, I looked with an engine just now to check my analysis and look at yours and 27. Nd2 Rd8 28. Rxe5 is correct (not 28. Nxc4? after which black is back in the game) Bb3 29. Nxb3! (in your analysis you gave the inferior 29. Ree1? Bxd1 30. Rxd1 after which it is "only" +1...with low time Nxb3 might be hard to calculate a few moves ahead though) Rxd1+ 30. Kf2 Rb1 31. Re2 and then white is clearly winning. But with only a few minutes on the clock it's understandable you missed it. 

Would you play positionally against me?

I would normally avoid Schliemman and King's Gambit, which are not only tactical (and although I consider myself a good tactician, I'm not anywhere close to you) but which you also know better.

Instead I would play something like the White side of the Slav. 

Should you know more than one opening?

I wrote this piece years ago to answer that. http://www.bookup.com/bobby-fischers-chess-opening-secret/

As the OP states, "At the beginner levels, it should be opening concepts."

One of the better ways to do that is to study dissimilar openings. Where your favorite opening has a certain set of tactical motifs, a different opening will have pawn levers and such that don't work in your favorite opening. By studying the "other" opening you'll learn why the motifs work in one opening but not the other. This will give you the understanding of those concepts that everyone says beginners should be pursuing.

what happens if your opponent deviates from that one opening that you study? I've found it useful to use opening principles when opponents play something i don't study or don't know.

Besides the obvious benefit of learning to play more middlegame positions correctly, just looking at your repertoire, I find it hard to imagine you playing for a win with the Trompowsky/Colle, though I don't play those myself so I can't really say. All I can say is that theoretically at the top level it is "interesting, but equal".

So your repertoire is good against a tactical player, but it may be hard to play for a win against a likewise positional player. And if someone has a purely tactical repertoire, then your repertoire would work well.

But chess is a game and we all have different viewpoints about how it should be played. And at the end of the day, it is difficult to say whose viewpoint is the best .

That's really the problem, right?  What do you do when the opponent deviates from that one opening that you study?

First, if your opponent is deviating, he is probably playing an inferior move. If you are strictly memorizing then you may not have the opening principles to figure out how to punish the deviation.

That gets addressed in this PDF: http://www.bookup.com/BreakingtheChessGameAddiction.pdf

In a 2006 GM John Nunn book, in connection with opening study, it is stated that, if a "book contains illustrative games, it is worth playing these over first", and the reader was also advised, "To begin with, only study the main lines - that will cope with 90% of your games, and you can easily fill in the unusual lines later."

"... I feel that the main reasons to buy an opening book are to give a good overview of the opening, and to explain general plans and ideas. ..." - GM John Nunn (2006)

In one of his books about an opening, GM Nigel Davies wrote (2005), "The way I suggest you study this book is to play through the main games once, relatively quickly, and then start playing the variation in actual games. Playing an opening in real games is of vital importance - without this kind of live practice it is impossible to get a 'feel' for the kind of game it leads to. There is time enough later for involvement with the details, after playing your games it is good to look up the line."