I'm sure of two things:
(1) playing open, classical chess is the best way to improve your tactical ability; and
(2) improving your tactical ability, if you can do it, is the best way to improve your overall strength.

But isn't it also true that, if you are still weak at tactics after playing for years, your tactical ability probably isn't going to improve much whatever you do? 

Nigel Davies, who has a lot of experience in coaching adults of modest talent, suggests that for such people the training benefits of playing sharp positions are outweighed by the likelihood of blunders. (I paraphrase, but I think that's the gist.) He recommends an alternative approach: study endgames, and play dull stuff like the London system and the Fort Knox with a view to getting into the endgame as quickly as possible. 

Markovich, is it your view that all mediocre adult players can learn to play sharp positions well -- or at least better than they do -- if they go about it in the right way?

I wouldn't say that a desire to play an open game requires an Open Sicilian; the Alapin generally leads to rather open positions (IQP for example).

I am an adult (51 years old) but in terms of chess still a junior I suppose...I just started playing 5 years ago.  My background is in engineering so my natural inclination to investigate all possibilities led me to play around with virtually every opening there is to see how I did.  Of course, I was neglecting the very things I should have been spending my time on:  tactics and basic endgames.  As one website says, there is a name for a person who spends all their time studying openings:  "a perpetual novice".

Over the last 6 months I think I finally started to see the light.  Studying openings is quite fun, but winning is more fun.  I have been relentlessly studying tactics and I think I have the basic endgames down (at least the ones up to class A in Silman's endgame course).  Because of my home's location, I still have not played the 20 rated USCF games I need for an official rating, but based on the tournament games I have played and OTB games locally against rated players I would place my rating at about 1500 or so.

For what it's worth, I am showing my current repertoire below.  My emphasis was on open games (ala Markovich) and streamlining the repertoire so that I can focus on the middlegames.  I do still have one problem area in the repertoire (noted below) and would welcome suggestions there.

White

1 e4

1...e5: 2 Nc3  Now against 2...Nf6 I play 3 f4 (Vienna Gambit) and against any other second move I play the Scotch 4 N's with an occasional Belgrade Gambit if I'm in the mood

1...c5: 2 Nc3  Against 2...Nc6 I play 3 Bb5, against 2...d6 I play 3 f4 and against the rest I will either play 3 Nf3 or 3 d4

1...e6 and 1...c6:  I play the exchange lines with 4 c4

Basic stuff against the Scandinavian, etc

Black

1 e4 e5 with Two Knights and usually deferred Steinitz against Ruy

Tarrasch setup against everything else

My one problem area is the white side of the Sicilian.  I am constantly torn between my desire to play an open game (which requires an open Sicilian) and my desire for an economical repertoire which my current approach (or the Rossolimo/Moscow) achieves.  Any advice in that area would be appreciated.  I know that there are low theory lines in the open Sicilian with 6 Be2 but though they give a more open game are they really more effective than the Bb5 lines?

Sandman wrote on 09/29/09 at 21:17:53:

As indicated elsewhere I tend to disagree a little with this. However with adults it is very often that they are "set in their ways". Meaning that they have neglected certain areas of play over the years (very often open games, but endgames or closed games are not uncommon either). So yes if you feel you are missing out in that department, go for it.
Quote:

I dont see why an adult would have more or less difficulty learning this. The problem with adults usually is economy of time. They work, have families and cant spend all their spare time behind a chessboard. 
Having said that, learning the KG is not more difficult than taking up the QG as you have done. The point is that you just have to start playing it (adults often have the tendency to only play openings they feel they have really learned, while youngsters on the other hand often think they completely understand an opening after having spend a couple of days on it).
Personally I think you could do worse than switch to more open games, but if you dont and dedicate a lot of time to tactics and playing through Morphy et al that may be just as well.

I'd like to thank everyone for their comments and hope the opinons and suggestions continue.

Personally, I taught myself to play chess many moons ago and I've always played a closed positional game not really having an actual repertoire. I'd play a KID formation type of game from both sides of the board. Not until I ran across Markovich's Hard Chess column years ago did I develop a repertoire as I emulated his QG rep for white and adopted the tarrasch as black.   

I peruse this board fairly frequently and have noticed the emphasis placed on open games and it makes me wonder if class level adults that wish to make it to expert should also play this way. 

As mentioned in the "openings for junior" thread, Markovich and Phil Adams advise: 

Phil Adams wrote on 09/16/09 at 18:00:21:


I believe in this fully for juniors and I wonder would switching from closed to open like this help adults also?  Should I discontinue my positional play and change to open games or is it a case of "can't teach an old dog new tricks" and I'm better off staying positional?  If it is advisable for me, or other adults, to change to open games then what openings (rep) should adults play? The same as those suggested for juniors? Can an adult learn the king's gambit and be successful? Would open tactical play be the key to crossing the magical 2000 barrier?

I stopped playing chess 30 years ago due to academic  studies and a carrier in the industry.  I actually didn’t play one single game during the first 25 years of the 30.
A couple of years ago (just retired and become a senior citizen) I took up chess again – all chess on internet was new to me!!  Previously I had boxes with cards on which opening variations were written by hand. The same thing for middle game and end game – a lot of cards in boxes. Cherón was THE reference in the end game and Averbakh was showing up in English.
When I took up chess again (played like a child!) I wanted a repertoire quickly to be able to take me through the opening to be able to play some middle games and end games before losing. I used “Chess explained” which actually helped me lot. 
Now I am converting  to 1.d4 since that is more to my nature. I think it is extremely helpful to have (build) a repertoire. You get the possibility of playing similar and related middle game positions and improve playing these positions. That is very stimulating.
It is very difficult to start building up a repertoire from scratch. I think it is an advantage if you can find openings/variations that could give closely related middle game positions or perhaps even transpose into each other. Usually you don’t have that knowledge from start and you certainly don’t really know what openings you really like to play. It is a very time consuming (but pleasant) task.
Currently I always stick to my repertoire and if I am exposed to a new move I analyse it and then add my reply to the repertoire. I enter it in Bookup/CPT together with all relevant comments I find in books, magazines  and on the net. If I don’t like a move in my repertiore (over some period of time) I just weed it out and substitute it with a line I think is better (according to my personal preferences).
I find it very comfortable to have a basic repertoire (start small) which I can extend when I get more experience and will get a better understanding of the openings I am playing. Currently I have a very shallow understanding but it will improve as I get more practical and theoretical experience. 
I think it does free time to spend on middle game and end game to have a small repertoire and actually while working with the repertoire I am learning more about especially the middle game but also to some extent the end game.
I do agree with Phil Adams that says that it depends on a lot of different things when you build up a repertoire and also how you will build it. If you just learnt how to play then you actually are a beginner and then more should act according to Markovich advice – open game and tactics. As a matter of fact it is not a bad idea to have a second repertoire, if you got the time and interest, to train the tactics in real play even if you are “a grown up”.
My small experience tells me that it is very important to start out small and then extend/change in pace with your experience but try to be consistent.
If you just want to play for the hell of it then it’s no bad idea to test all different openings. Perhaps some time you will find that you are using some opening moves more frequent than others.

A lot of the advice given seems to assume that one already has some sort of repertoire, and that the question is whether to change it, and if so how. I've been playing for a long time, but would still have difficulty in saying what my repertoire consists of. In fact I have difficulty remembering what openings I have played in the last few months! I keep playing openings I don't know much about, because there aren't any that I do know much about. Of course the answer is to learn some; but which? Where to start? If you start playing the open, classical stuff that you should have been playing in your youth, you're going to throw away a lot of points (for your team as well as yourself) while you learn the theory, unless you give up playing until you have learned it. So there is a strong temptation to go for something less theoretical. But that merely postpones the problem rather than solving it.

I don't know how typical this dilemma is. I bought Steve Giddins's "How to Build Your Chess Opening Repertoire" on reading that he too didn't have much of a repertoire until he studied with a Russian coach. Unfortunately, despite the title, he doesn't really explain what to do about this state of affairs if you don't have a coach (Russian or otherwise) to advise you.