I can tell you that Bird's opening is interesting. Not necesarily good but interesting. White will give up his theoretical advantages to reach positions that very few players have studied theoretically and thus have to play real chess. It's a good choice to play against people that feed of of opening prep and traps to force them to think from move 1. About your opening dillema i would say you are taking a solid step in the right dirrection. A Grandmaster is a master of all facets of the game and knows how to play all kinds of positions.
Sicilian

You want to train your attacking skills? Then play Open Sicilian as white, not Closed Sicilian.
Yes, in the Closed Sicilian white can get an attack but Black plays ...f5 at the right moment and bam no attack for you...
The Open Sicilian has a bunch of theory but you need to remember that your opponents who play it won't know all the lines either...
Use your database and see white's major plans of attack in the Open Sicilian-especially the Scheveningan variation since that structure is often considered the "cornerstone" of other Sicilians. Look for those piece sacs on e6 and d5. You want to improve your tactical ability and play Open Positions so why play Closed Sicilian?
1) Will the KG actually train my attacking skills, or will I be forced into passive positions since it is "refuted"? Should I try the Vienna instead?
2) Will the closed sicilian have plenty of positional play?
3) Will the sicilian or the Ruy be better (playing as black) to learn how to play varied positions?
4) What is the nature of the English / Bird's opening, and is it worth learning to play it to get experience of new positions?
Thanks for all your help,
Hypocrism
I feel like I can safely say you're not going to be forced into passive positions playing the KG. And it's not "refuted." It may peter out to equality at the super-GM level, but by no means is black finding advantages against all the mainlines. If anything can be said, it's that it has become a highly positional opening at the highest levels of chess. But even that isn't even close to holding true sub...I don't know...2500? Unless you're playing Polgar sisters regularly or something, it's still about as tactical and nasty as openings come.
On the matter of the Closed Sicilian...well, we know that it can take you as far as the world title, as your main weapon against 1...c5. That's probably all you need to know about it.
On the matter of Sicilian vs. Ruy (as black), I actually think 1...e5 is probably the winner here if the only matter is playing varied positions. Presumably, you'd play primarily one type of Sicilian, and at the ~1800 level, you'd probably see plenty of mainlines. Against 1...e5, you'll see a number of Ruys, a number of Italians, a number of KG's, a number of Viennas, a number of Scotches, and probably some Centers, Danishes, and whathaveyous. People wail and moan about how many anti-Sicilians they see, but in practice, I think you see a lot more variety against 1...e5.
On the matter of the English and Bird...I have no idea what you're asking, nor why you're asking it.

You are asking for a lot of studying in the future it seems.
I personally stick to only 1. d4 because there are so many variations with 1. ... e5 AND 1. ... c5. Don't forget other replies like c6 or e6.
Playing the Sicilian requires a lot of knowledge. To play an open sicilian will require a lot of studying. I've spent countless nights studying Najdorf theory and I still have loads of studying to go. Studying will pay off. I'm rated almost 1700 in USCF and I was able to spot the slight error in a Najdorf game I played against a 1900 where just a move Kb1 to bring your King to safety can be very dangerous.
Closed Sicilians can, for the most part be played with positional ideas, but you must be able to mix both positional and tactical ideas, a very hard and acquired ability(I have so much difficulty with this).
1) King's gambit will test your attacking ability. If you do not grab the initiative, your opponent will, and you have no f-pawn to guard the opponent's queen from h4 with check.
2) Closed sicilian will offer positional play, but you must understand why you are doing what you are doing. It deals with pawn breaks and controlling the center.
3) Both Sicilian and Ruy Lopez contain loads of theory. MCO-15, which I'm also studying from, contains dozens of pages for each. The difference between Ruy Lopez and Sicilian, from a black perspective is that many different Sicilians can be played in similar manners(ie many Closed Sicilians can be played with the same opening moves and Opens with their own set of moves), but a Ruy Lopez must be the opening WHITE chooses. You also have to learn theory for the Scotch and the Italian games.
4) The ideas behind these openings is that they control the center without putting a pawn in the center. The Bird opening can lead to KG games or reverse Dutch defense games(I think, I'm not sure because I haven't studied this). The English can lead to the same openings as d4 if your opponent plays c6(leading to slave after 2. d4 d5), e6(QG after 2.d4 d5) or Indian games (after 2. d4). None of these black response need to be followed with d4, however.

It's not much study at all. To play the Open Sicilian reasonably well, just learn the English Attack, some basic ideas in a few other systems and something against the Dragon. That's almost as little work as the Closed Sicilian with far more benefits.
An improving player should learn the 1.e4 e5 games. What better way to learn them than by playing them?
If your goal is to have fun without improving, any opening system will be good enough.
If your goal is to maximise your imrovement, learn how to play the critical lines with 1.e4.
Since I'm probably switching back to my old repertoire, or at least being in a position to alternate between the two, after a year or so of playing this new one, do you think 1...e5 or 1...c5 will bring me the most overall benefit in terms of actual understanding, tactical training, and new positional ideas? I typically focus my opening training firstly on learning moves, and after that focusing on plans, tactical motifs - I learn the plans and tactics through trial and error as well as study after I've played my rote-learned book moves, I prefer that to directly studying plans before moves.
I've heard a lot of people saying that the sicialian is incredibly positional, even though I got the impression it had the reputation as being very tactical, double edged and attacking.
My aim is to improve - I have fun competing againt my own limits and other people. In a year I climbed from never playing competitively to being 3rd board at my school, below two highly rated players. That gave me the desire to get even better and taking up new openings I think is one of the first steps to understanding chess better.
Do you have any insights on the English / Bird?

Hi hypocrism,
There are many ways to learn. It really depends on your objective. Imo, it is better to master all aspects of chess. It is fine if you want to do what you are best at and avoid what you are worst at. But if you want to go high enough, there’s no option you have to master ALL aspects.
Let’s see your situation. You have chosen Caro-Kann and 1.d4/Slav. Whatever you have or will learn, make sure you know what do you want to achieve, in general and in detail. When using Caro-Kann for example, make sure you read chess endgame book (at least the associated topic i.e. pawn endgame), and before you leave the Caro-Kann, make sure you have achieved an acceptable level of playing pawn endgame.
With your 1.d4/Slav experience I can say that you are restricted to positional play. Bad news is, it is impossible to go very high with excellence positional play but lousy tactical skill. Even worse, tactical skill can only be mastered by playing frequently (and tactically). Theory doesn’t help much.
The good news is, the positional skill will help you a lot when you start to improve in tactical play. For example, you can make combination to achieve winning position (which is not clear if you are not good enough positionally). Currently I play KG but if I can see an option where I can have save position (exchanged pieces) and my opponent have one isolated pawn, then that is more than enough.
Knowing how to play various situations is usefull because you cannot control what situation that will come to you. Thus knowing more will improve the probability of winning. The opposite is true.
1) WILL KING’S GAMBIT TRAIN ATTACKING SKILL? IS IT PASSIVE AND REFUTED?
Imo, KG is a must-learn opening, in the topic of improving tactical skill, and sharpening your positional theory (advancement, tempo, initiative, imbalance, etc.). It is easy to learn, and how to play it requires certain positional knowledge. And the chance to be replied with 1…e5 is very high (same as the Sicilian 1…c5). And with KG, you are probably the one who get the most advantage because you are the one who most probably know it better.
Among all gambits, imo KG is the best. It takes a solid KG player to “refute” KG opening. If it is a fast game I think the chance is more than fair (you will find many are confused or even don’t have the knowledge to play such positions). In a long game, unfortunately, you have to know whether your opponent is a solid KG player himself before chosing the opening :( You should prepare another opening such as a Ruy Lopez, a variation of which the “feel” of the positions is familiar to you.
Yes, imo the KG is refuted. The biggest advantage Black can get is the mainline of the Fischer Defense (3…d6!), but to go this route Black must be ready with so many possibilities with playing under steady pressure from White. Imo, only KG player should choose this defense. Casual KG player should be better to refute the gambit. By refuting the gambit (Decline Defense, counter gambit 2…d5!) the situation changes up side down. It is White who is under pressure, but only positionally. Not really “passive” because it is an open position.
2) WILL THE CLOSED SICILIAN HAVE PLENTY OF POSITIONAL PLAY?
Imo, it is a waste of time studying this line. Are you trying to avoid open games?? There is nothing unique that you can learn from this opening. Open Sicilian is the best. Unfortunately it is the most difficult opening. But a must learn opening! You can avoid but nothing to gain for long time advantage imo.
By learning many openings, I can usually solve the “secret” of each opening, or the “refutation” and throw the opening into trash bin. For example, against the Sokolsky (1.b4) I just prepare 1…c6 and 2…a5 and the Sokolsky is “finished”. To “refute” the Closed Sicilian I just fiancheto the king’s bishop like in the Dragon variation. I have a lot less to memorize now.
3) THE SICILIAN OR RUY FOR VARIED POSITIONS (AS BLACK)?
What you’re looking for is not just varied positions, but typical UNIQUE positions that you can get from many openings, and type of positions that you CANNOT avoid.
Sicilian has many unique positions. If you are not afraid with the risk, I suggest playing the Dragon variation, but you must be equipped with theory.
Ruy Lopez is the mother of positional opening. It is just more dynamic than 1.d4 and can go very open. It is easier to understand than the Sicilian but has too many tactical variations to memorize. Imo, you can decide to forget playing Ruy Lopez as Black for the entire of your life. Enough for you to play it as White, and focus on the Sicilian as Black instead.
4) NATURE OF ENGLISH/BIRD. NEW POSITIONS?
I would say that KGA is one of the root of all opening positions, especially those result from 1.d4 and 1.c4. Once you understand the KGA, it is easy to stir any opening to that type of play. You will not be confused with 1.Nf3 or the like. It is a must-learn opening imo. Forget the Bird opening.
Playing English against positional player? No way. It is easily equalized.

Hi hypocrism,
There are many ways to learn. It really depends on your objective. Imo, it is better to master all aspects of chess. It is fine if you want to do what you are best at and avoid what you are worst at. But if you want to go high enough, there’s no option you have to master ALL aspects.
Let’s see your situation. You have chosen Caro-Kann and 1.d4/Slav. Whatever you have or will learn, make sure you know what do you want to achieve, in general and in detail. When using Caro-Kann for example, make sure you read chess endgame book (at least the associated topic i.e. pawn endgame), and before you leave the Caro-Kann, make sure you have achieved an acceptable level of playing pawn endgame.
With your 1.d4/Slav experience I can say that you are restricted to positional play. Bad news is, it is impossible to go very high with excellence positional play but lousy tactical skill. Even worse, tactical skill can only be mastered by playing frequently (and tactically). Theory doesn’t help much.
The good news is, the positional skill will help you a lot when you start to improve in tactical play. For example, you can make combination to achieve winning position (which is not clear if you are not good enough positionally). Currently I play KG but if I can see an option where I can have save position (exchanged pieces) and my opponent have one isolated pawn, then that is more than enough.
Knowing how to play various situations is usefull because you cannot control what situation that will come to you. Thus knowing more will improve the probability of winning. The opposite is true.
1) WILL KING’S GAMBIT TRAIN ATTACKING SKILL? IS IT PASSIVE AND REFUTED?
Imo, KG is a must-learn opening, in the topic of improving tactical skill, and sharpening your positional theory (advancement, tempo, initiative, imbalance, etc.). It is easy to learn, and how to play it requires certain positional knowledge. And the chance to be replied with 1…e5 is very high (same as the Sicilian 1…c5). And with KG, you are probably the one who get the most advantage because you are the one who most probably know it better.
Among all gambits, imo KG is the best. It takes a solid KG player to “refute” KG opening. If it is a fast game I think the chance is more than fair (you will find many are confused or even don’t have the knowledge to play such positions). In a long game, unfortunately, you have to know whether your opponent is a solid KG player himself before chosing the opening :( You should prepare another opening such as a Ruy Lopez, a variation of which the “feel” of the positions is familiar to you.
Yes, imo the KG is refuted. The biggest advantage Black can get is the mainline of the Fischer Defense (3…d6!), but to go this route Black must be ready with so many possibilities with playing under steady pressure from White. Imo, only KG player should choose this defense. Casual KG player should be better to refute the gambit. By refuting the gambit (Decline Defense, counter gambit 2…d5!) the situation changes up side down. It is White who is under pressure, but only positionally. Not really “passive” because it is an open position.
2) WILL THE CLOSED SICILIAN HAVE PLENTY OF POSITIONAL PLAY?
Imo, it is a waste of time studying this line. Are you trying to avoid open games?? There is nothing unique that you can learn from this opening. Open Sicilian is the best. Unfortunately it is the most difficult opening. But a must learn opening! You can avoid but nothing to gain for long time advantage imo.
By learning many openings, I can usually solve the “secret” of each opening, or the “refutation” and throw the opening into trash bin. For example, against the Sokolsky (1.b4) I just prepare 1…c6 and 2…a5 and the Sokolsky is “finished”. To “refute” the Closed Sicilian I just fiancheto the king’s bishop like in the Dragon variation. I have a lot less to memorize now.
3) THE SICILIAN OR RUY FOR VARIED POSITIONS (AS BLACK)?
What you’re looking for is not just varied positions, but typical UNIQUE positions that you can get from many openings, and type of positions that you CANNOT avoid.
Sicilian has many unique positions. If you are not afraid with the risk, I suggest playing the Dragon variation, but you must be equipped with theory.
Ruy Lopez is the mother of positional opening. It is just more dynamic than 1.d4 and can go very open. It is easier to understand than the Sicilian but has too many tactical variations to memorize. Imo, you can decide to forget playing Ruy Lopez as Black for the entire of your life. Enough for you to play it as White, and focus on the Sicilian as Black instead.
4) NATURE OF ENGLISH/BIRD. NEW POSITIONS?
I would say that KGA is one of the root of all opening positions, especially those result from 1.d4 and 1.c4. Once you understand the KGA, it is easy to stir any opening to that type of play. You will not be confused with 1.Nf3 or the like. It is a must-learn opening imo. Forget the Bird opening.
Playing English against positional player? No way. It is easily equalized.
This is a great post, but I would like some more information about the difference between the open and closed sicilian.

This is a great post, but I would like some more information about the difference between the open and closed sicilian.
The open sicilian is very open with many possibilities. White is superior but the position is very complex so Black has equal chance of winning because of the complexity and the difficulty in playing it.
With the closed sicilian, you better look at line where Black fiancheto his king's bishop. As it name implies, it is closed. No way white can complicate it for his benefit. The closed position itself resembles closed positional positions, with Black has positional advantage.
Imo, Closed Sicilian is not the right way to choose positional game. But if Black doesn't know what to do (i.e. fiancheto the king's bishop) usually Black will have many problems.

4) NATURE OF ENGLISH/BIRD. NEW POSITIONS?
I would say that KGA is one of the root of all opening positions, especially those result from 1.d4 and 1.c4. Once you understand the KGA, it is easy to stir any opening to that type of play. You will not be confused with 1.Nf3 or the like. It is a must-learn opening imo. Forget the Bird opening.
Playing English against positional player? No way. It is easily equalized.
I think you're talking about QGA here, which is, as you say, a root of many opening positions. KGA, not so much.

I would say that KGA is one of the root of all opening positions, especially those result from 1.d4 and 1.c4. Once you understand the KGA, it is easy to stir any opening to that type of play. You will not be confused with 1.Nf3 or the like. It is a must-learn opening imo. Forget the Bird opening.
Playing English against positional player? No way. It is easily equalized.
I think you're talking about QGA here, which is, as you say, a root of many opening positions. KGA, not so much.
Thanks. You're right, I was talking about QGA.
I'm currently revamping my opening repertoire using MCO 15 and a database to see opening lines. I'm not very highly rated (my chess.com live standard rating is quite stable at the moment if you want to have some comparison point) but really enjoy opening theory. Basically when I first decided on a repertoire a year ago, I chose the Caro-Kann, 1.d4, and slav as my openings of choice, because I enjoyed the idea of positional chess and solidity.
Now I realise I'm restricted to a certain way of playing, because I don't have enough experience of other ways of playing - in particular, sacrificial attacks, more sound attacks, and general tactical ability in more open positions. In the end when I get a better opening repertoire (I do not know if I will stick with this one) I want to be able to have more knowledge in situations where I currently feel uncomfortable.
I want to learn to play 1.e4 (why not know both major opening moves?) but specifically want to learn the following openings to black's major replies:
King's Gambit
Ruy Lopez
Closed Sicilian
I also want to reply to 1.e4 with the sicilian or 1...e5, and to 1.d4 with the Nimzoindian.
I'm doing this to force myself into different types of positions (KG especially), to force my tactical vision to improve, and to force discipline at the board so that I don't fall into traps because of my confidence in the positions I think I "know".
What I really want are some reccomendations -
1) Will the KG actually train my attacking skills, or will I be forced into passive positions since it is "refuted"? Should I try the Vienna instead?
2) Will the closed sicilian have plenty of positional play?
3) Will the sicilian or the Ruy be better (playing as black) to learn how to play varied positions?
4) What is the nature of the English / Bird's opening, and is it worth learning to play it to get experience of new positions?
Thanks for all your help,
Hypocrism