Sicilian Dragon 9.Bc4 or 9.O-O-O ?

Which of these two moves is better in the sicilian dragon yugoslav attack? I have heard some people say that 9.Bc4 is better, but others prefer 9.O-O-O.

I do not know why my moves on the chessboard are not showing up... If anyone can show me how to insert a chess game into the forums correctly, please do so!

I prefer castles queenside on move 9, or playing g4!?

after 9.0-0-0 d5 I’d play Qe1, where black can be fine if he walks a tightrope.

9.Bc4 prevents d5 Fischer

0-0-0 basically forces black to sac the d pawn

I always play 9. 0-0-0 to save the tempos with my Bishop. I'm not worried about 9...d5 as White is OK in those lines.

9. Bc4 is a bit more work (i.e., more theory) to play, but with a precise attack, Black's defense is tough.  I play it in correspondence games (which is most of the chess I play these days).  Over the board, I might prefer 0-0-0.

Objectively they are equal, but radically different. I play the Dragon, mostly with Black, and prefer to see 9. Bc4 rather than 9. O-O-O. The Bc4 lines are more aggressive and in the spirit of the Yugoslav. White gets good attacking chances but gives Black good ones as well. The 9. O-O-O lines intend to bind Black positionally and generally White is not attacking on the kingside whatsoever and instead trying occupy squares in the centre.

The problem with 0-0-0 immediately is that it allows the d5 break and with it, a lot of simplification and no attacking chances for either side. After Bc4 though, White's attack comes faster, and Black has to defend accurately, so it seems to me you're turning down a free attack, unless you just really like positional play I guess.

i think the main advantage of 000 is actually it encourages d5, which probably equalizes for black but also lacks the dynamic character black would likely want to keep in his position. maybe white can grind something in the equal positions and hope black gets frustrated. with bc4 i don't know of so many quiet or dry positions. i have not tested 000 or bc4 in an actual game but i have played the dragon myself and i quite like facing bc4, but i don't feel as inspired with 000.

The same story with me... this is main puzzle for me  on chess.com ))

when 0-0-0 is played instead Bc4 and black goes d5, it is most likely that white will seek for endgame advantage considering better pawn structure on queenside.

When the world best 2 players (Stockfish and Leela ) agreed 9. O-O-O together, it is the answer!

I like queen-side castling and then trying to force black to trade off his dark square bishop with Bh6

How do you get that GUI interface? And how do you read what it evaluates for 9.Bc4 ?

And I thought engines were supposed to not be relied on for opening analysis.

It is Arena GUI, 

I can do evaluation of 9. Bc4 by doing 3 Multi PV. ( I guess it is the third choice after O-O-O and g4. Drawback of 3 Multi PV is that Stockfish will be only 33% power of single PV)

That was myth 20 years ago. Yes, at that time, engines play 1. Nf3. 2. Nc3 Two Knight Tango etc.

And my analysis has more than 250 million nodes from Stockfish and also there is 6 men Tablebase set up.

The GUI is Arena, and yes, it is quite apparent that engine evaluations at that stage of the game are completely useless. From that position there are hundreds of thousands of games, dozens of thousands of modern correspondence games, and (if someone trusts engine aided games that much) some 6,000 high level correspondence games played in the last 10 years.

Browsing any set of the above games is one hundred thousand times more infomative than the clumsy engine dump that drmrboss has posted.

So which is objectively better, 9.Bc4 or 9.O-O-O ?

Both are equal with best play from both sides. I am positive that Black's task is more difficult against 9.Bc4, when a slight inaccuracy may well spell doom, but personally I have always played 9.0-0-0 (and occasionally 9.g4) as I am too lazy to learn all these lengthy lines starting from 9.Bc4.