opening choice for 1900 Fide

@BonTheCat Thanks for your messages. I am looking for a second weapon against e4 which will also help me improve my understanding on some chess positions. As I only played the najdorf for now, my understanding is quite limited (especially in the pawn structures).

Maybe I should give the CaroKahn a try. I would also be tempted by the other Sicilian variations you proposed but probably I would learn less than with a new opening (and still requires a lot of theory as the Taimanov and Kan are very sharp as well)

Against d4, will have a look at the Benko proposed by pfren. No one really proposed the Grunfeld or the QGD 

What was it that you liked about the Najdorf?

Perhaps by answering that question, it will be easier to find a good second defense to 1.e4.

@SmyslovFan : I like the sharp aspect of it, but I also feel like to improve I should learn more "boring" and "balanced" pawn structures openings

@Optimissed : I started to look some games with the CaroKahn and it looks very passive to my eyes. 

https://www.youtube.com/watch?v=8W09NwT1fTk&t=411s 

I would prefer to play white in such variation. But will have a deeper look.

I'd agree with Optimissed regarding the French and the QGD, although I'd personally say that you're better off starting with the Caro-Kann - it's easier to master than the French - even though, arguably QGD in some respects is a slightly closer companion to the French than the Caro-Kann. It's worth noting that many strong players who play the French or the Caro-Kann against 1.e4 often play the QGD against 1.d4.

As for playing the Volga/Benko, it shares many traits with the KID and the Benoni, so you really can't go wrong there. That said, you'd better have a good look at the 5.b6 variation. In my view, White gets a tiny, but very pleasant edge, and Black doesn't get anything close to the normal Volga/Benko play.

However, if you're out to broaden your style, you should at least experiment with the QGD.

Black's game in the Advance Variation is based on the coiled spring effect - it looks scary, but is generally perfectly OK for Black. If I were you I'd look up the theory in a book rather than just a video. GM Lars Schandorff (who, as opposed to Maxim Dlugy, is actually an active, and not a semi-retired, grandmaster) has written a good one recently for Quality Chess. Schandorff has made the point that when White is throwing the kitchen sink in the Advance, Black tends to be perfectly fine. The most critical variation is actually the slower Short set-up with Nf3 and Be2. Also, you should look at the games of the biggest Caro-Kann players, starting with Botvinnik, Smyslov, Bent Larsen (he played the Caro-Kann in a very enterprising manner in the 1970s and 80s), Vladimir Bagirov (one of those Soviet talents who were too old once the Berlin Wall fell - he used to play the Alekhine and the Caro-Kann against 1.e4 - his games in the Advance variation especially, but also the other variations are well worth studying) and Karpov and more recently, Leko, Dreev, Bareev, Shankland (who seems to use it or the French as an alternative to the Sicilian) and David Navara. These days, even players like Ivanchuk and Mamedyarov play the Caro-Kann!

@pfren : Why would you suggest this opening? Why does it help getting better?

I didn't say the Kan Sicilian was easy, especially after the maroczy bind

For e4 I can recomend the ponziani or the center attack variation of the giuoco piano.

I never use d4 but everyone plays the queen's gambit and it has very good stats. To defend the queen's gambit I always go for the semi-slav

pfren: French and Caro-Kann are primarily positional in character and as such, far less high-maintenance than virtually any Sicilian variation.

blackpopa: Come to think of it, if you don't like the look of the Caro-Kann in the Advance Variation, you have to bear in mind that in most French variations, you'll find yourself with a similar structure as Black. Clearly this has not deterred many of the greatest players in the world - from Capablanca and Botvinnik onwards to Korchnoi, Wolfgang Uhlmann, Karpov, Vaganian, Short, Lputian etc. - from picking up the French as an important weapon against 1.e4. Especially the games of Vaganian and Lputian are worth looking into. Very creative players who both played QGD (in particular the Tartakower variation) and the French Defence.

I agree with @pfren, with the following proviso: You should analyse your openings and see how you do with them in serious games.

Tigran Petrosian once wrote that if you lose three times in a row with the same opening, it's time to consider changing your opening. Well, not too many people here are GM strength, but if you lose five times in a row with the same opening, there may be something wrong with the way you're playing the opening, or perhaps you don't understand the resulting middle games properly.

Pardon me for saying so, but this is a very odd comment. When I was E1900 I thought I knew a lot about chess. Then I improved a bit more and realized that I actually still had big gaps in my chess knowledge. blackpopa specifically says he wants to broaden and deepen his knowledge with another main line opening and tells us what openings he currently plays. I wish I had done the same when I was E1900, instead of wasting time trying out rubbish openings on my own.

 I'm not going to disrespect you by saying that you clearly know nothing about chess if you take that attitude. There's a lot of received wisdom in chess which on closer scrutiny turns out to be incorrect or needs to be severely qualified, and unless you're a genius you're likely to go along with much of that received wisdom by default. You may not think it helps to ask for input on this from others, but I strongly disagree. I'm not just talking from my own experience; I've come across IMs and GMs who completely lack insight and judgement in these matters (one former super grandmaster springs to mind), but much more importantly also IMs and GMs who've said that one of the many important facets of their growth as players was that they regularly discussed various aspects of chess, including openings, with their peers. In short, I - and clearly many others - most certainly do think that a 1900 player would benefit from asking for advice from others. Apparently blackpopa is thinking along the same lines when he asks for input.

If you think we're idiots for doing so, that's your business, but I then suggest you keep that opinion to yourself, since you're highly unlikely to be able to contribute anything of value to the discussion.

Greg Shahade just posted something on Facebook that I agree with: there's a lot of uncertainty out there, and there are many "correct" ways to improve. There's no one correct way, and people who claim that some specific advice is *always* good or *always* bad, is "either pompous, a charlatan, or an idiot". 

Personally, as a life-long educator, I believe that the connections we educators make with our students are just as important as the material we cover. 

So you play najdorfs and KIDs and want to add more.

I'd go with something classical, like 1.e4 e5 and QGD or Nimzo.

I think it's good to have some experience in both the sharp / hypermodern stuff as well as the more classical positions. Being well rounded enhances your overall ability IMO. Knowledge in one area of chess will unexpectedly help you out in other areas.

By the way I feel like the benko is easy to play... the hard part is the many many many options white has, but once you reach a mid game, I feel like it's easier for black than white.

And all of those are pretty time/work intensive openings.

The nice thing about adding the QGD as black is you can nearly start playing it right away. All the moves are pretty natural, and the ideas are straightforward... at least compared to KIDs and Najdorfs.

Meeting 1.e4 with 1...e5 would take a lot of work though if you've only been playing the Sicilian.

Yeah, very few people go for the full benko with their c pawn ending up on a6.

Maybe they're afraid it's what black has studied most?

But just form my limited experience playing it, it's what I have the least experience in because it's so rare that I get to play it

Well when white doesn't capture on b5 I almost always capture on c4 right away.

When white captures on b5 but not a6 I almost always capture on b5 right away.

I say almost always because there are probably some variations where I'm not supposed to, but just from memory it's what pretty much always happens (there are so many ways to decline I still need to review heh).

I saw chessexplained play 4...Bb7 over and over, and it seems to be the 2nd most popular move in the database. I don't really understand it though, the positions it leads to don't seem very benko-esque to me, and white has some drawish looking lines which is not what I want when I play a bekno.

It seems like 4...g6 just transposes so I don't really get it. As far as I can tell after g6:

5.cxb transposes into 4.cxb lines
5.Qc2 transposes into 4.Qc2 lines
5.a4 transposes into 4.a4 lines

And 4.Nf3 b4 seems slightly inaccurate for black because in other lines black is playing Qa5+ first to discourage Nd2. For example

And sure enough, when I look at 4.Nf3 b4 the most popular move is 5.Nd2

So I guess I'd play 4...g6 and ask why we're not transposing into something you could have played on move 4 anyway.

And that's a real question  I don't know if it transposes.

I don't have opening books, I use databases and look at games and an engine to make sure none of the lines I choose to truly bad.