Neither of these games led to opening positions which I would want to play as white. Also note Kasparov played it, so it's not just some random rubbish
Playing The Catalan System, Part 1: Basic Principles and Main Variations

I'm sure he means when black plays c6.
I guess it wasn't obvious. The Slav is 1.d4 d5 2.c4 c6.
I thought he was talking about the closed catalan with exchange of black square bishops, which I posted in #19, and gave a nice explanation video link in #22. The NM never clarified what talking about though. Still think it is a pretty easy line for black to learn, and fits nicely with the Bogo if black plays that.
Otherwise white can avoid this and other lines by delaying d4. In that case would recommend solid 1d d5 club players just to play the main line. In post #54 play 5...0.0 60.0 then play 6....d5xc4, then solve the bad bishop problem with a6, b5 and bb7, or bd7-c6 depending on what white does. Also look for right moment for c5 break.
This line was played by Geller and Karpov for decades. Never understood what white has supposed to have found to generate any pressure, and what ever it is, it is too subtle to have much effect in club player games.

@twomove, I thought he was talking about the Slav in post #17, and he responded to your comment about the Bb4 line in post #21.

This game http://www.chessgames.com/perl/chessgame?gid=1604585 fits the story of his post. The fact that five years later not sure what he was talking about, shows clarity would have been helped by positing actual moves.
The NM responded to my post of Bb4 line with bishops being exchanged, with a different Bb4 line with a5.

How does it transpose from the Ruy Lopez? I didn't read the rest though.
Uhm...He said it can arise from "many" openings, not "all" openings. Basically it can arise from just about any "Classical Queen Pawn Opening" (meaning no fianchetto by Black) except for the Slav. White can try to play it against the Slav, nothing stops him, but the idea itself is just horrible for White.
http://gyazo.com/d3f9527ae5fe4d507f82661407258cf6
I have red this too. Transpose of a Ruy Lopez and from an King Indian attack. Well I was also curious.
Becuase a Ruy Lopez. 1.e4 e5 2.Nf3 Nc6 3.Bb5 I can t see this is transposing to 1.d4 Nf6 2.c4 e6 3.g3 d5 .
Also a King Indian attack with d3 does not belong to the Catalan. There d4 is played by white.

Yeah, if Black goes with the Slav, it makes White Bishop useless (show me otherwise) and a pawn is hung also.
Sorry to say you are totally clueless.
Here the 2800+ rated player did not even attempt to hang on his extra pawn, and had to play very carefully to maintain the balance.
When I play black I lways try to play a Nimzo Indian or Queens Indian but it can also become a Catalan. After the moves 1.d4 Nf6 2.c4 e6 it can become 3.Nc3 Bb4 a Nimzo 3.Nf3 b6 a Queen Indian or also 3.g3 d5 a Catalan. I know the Catalan often also occurs after a diffent move order. Like 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.g3
Also I know that after 1.d4 Nf6 2.c4 e6 3.g3 d5 ( the move order I am used to ) 4.Nf3 Be7 5.Bg2 0-0 6.0-0 black can opt for c6 a solid closed variation. But after the Slav 1.d4 d5 2.c4 c6 3.Nf3 Nf6 mostly white plays then 4.Nc3 or 4.e3 a Meraner. But I never realised that also 4.g3 was an option. I did not see this move often after a Slav move order. I did not know that also this was named a Catalan. I thought it must be a Slav. But anyway.
Pfren isn't exactly being accurate here, since the Closed Catalan ...dxc approach is a perfectly viable method of combating the Catalan, although it takes careful handling by black, as he pointed out. But that doesn't make it nonviable. It can be an attempt to win as black.
Also, the aggressive insults against another player are not pleasant for anybody to read.
I agree with the "aggressive insults" part of your comment, but the rest doesn't make sense to me. @pfren gave a game in the Slav, not in the Closed Catalan, and neither he nor @RubenHugenout said anything about it being nonviable
... I think I'll occasionally point out this aggression when it happens.
Referring to something that was posted on April 29, 2013?

Pfren isn't exactly being accurate here, since the Closed Catalan ...dxc approach is a perfectly viable method of combating the Catalan and blah blah blah blah...
Son, I am very sorry for you being that thick.
After ...dxc it is not a closed Catalan already, but an open one.

Pfren isn't exactly being accurate here, since the Closed Catalan ...dxc approach is a perfectly viable method of combating the Catalan, although it takes careful handling by black, as he pointed out. But that doesn't make it nonviable. It can be an attempt to win as black.
Also, the continual, aggressive insults against another player are not pleasant to read. After suffering this myself and others being fine with his bad manners and bombastic approach "because he contributes so much" I think I'll occasionally point out this aggression when it happens.
What does "Closed Catalan dxc approach" mean? Seems oxymoron
If I am following the review at
https://web.archive.org/web/20140627015209/http://www.chesscafe.com/text/hansen63.pdf
correctly, the "Closed Catalan" refers to:
or (presumably) an equivalent transposition.
If I following the review at
https://web.archive.org/web/20140627015209/http://www.chesscafe.com/text/hansen63.pdf
correctly, The "Closed Catalan" refers to:
or (presumably) an equivalent transposition.
These days the Closed Catalan usually includes a bishop check:

Pfren isn't exactly being accurate here, since the Closed Catalan ...dxc approach is a perfectly viable method of combating the Catalan and blah blah blah blah...
Son, I am very sorry for you being that thick.
After ...dxc it is not a closed Catalan already, but an open one.
I really hope you aren't this arrogant and rude in person Pfren?
All he did was say you where being inaccurate and you call him 'thick'!
Honestly you have got to be one of the most disgustingly arrogant and foul people I have ever laid my eyes on.
Regarding the "way to play the QGA", white doesn't have to go 5. cxb5 .... white can play 5. b3. In either case, white seems to get a pleasant enough game.
6.b3 (which I presume you meant) is met with 6...Bb4+ 7.Bd2 Bxd2+. I think it's quite telling that Vladimir Kramnik, who faced this a number of times, never seems to have played 4.e4 - why exactly do you think white has a pleasant game after these lines?