Ruining a great position in my first semi-final

In this game you can see that I am not really able to calculate even simple positions.  Perhaps some of you can tell me more about my mistakes. I didn't check the game with an engine, and I hope you will first try to use only your brain. At the end we still can check with a computer to see what really happened. Thanks for comments.

 

11...c5 is the first move I would think of too. Bf6 makes sense too, but there is no hurry. Bf6 can be played later, if necessary.

I think 12...Nxf6 is the more natural move. The knight can go to e4 if white plays d4.

I don't see the point of 15...c4, closing the queen side is bad. It isn't closed yet though. Black wants to prepare for opening the queen side with cxd4. You could double on the c-file and/or put the knight on f6.

Instead of 18...b5 you could have played Qg6 immediately, which is clearly a better move-order and also allows Nf6.

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Thanks Numquan. I have to begin again to write my ideas, as I cannot remember the reason I played 12...Qxf6, which I also think it is the most natural move. 

18...Qg6 seems better, sure, It comes with tempo so the c4-pawn is still protected. The knight unprotected on d7 and undeveloped was one of the reasons that my position collapsed.

What do you mean with lost by move 9? Why? 

Black is better at move 9, I guess

I thought to play Rb2 and Rc2, attacking c3. I thought on Rb1+, but I  not sure that this will be much better. 

Interesting, I read all your comments and didn’t find anything valuable,  but I know you already and I could not expect something else then these cliches. In your mind chess is very easy if you are confident, and questions about pawn tensions can be basically be solved by any player who knows how to move the pieces. Your sentences really sound like the things criticised in the book Move First, Think Later. I recommend you to read the book.  

After 8.Ne5, I think d4 is weakness. If push d5 pawn, b7 bishop will be active and in white and open d file for black.
So I think 8...Bc5 is better. If white try defend d4 pawn like Nf3, Nc6 will be attack.
After d4, If white play e4, Because of blocking b2 bishop, e5 square will be weak.

I think 9... a6 is pointless.
Maybe white intend Nc6 or Bc6 or Nxd7 or Bxd7.
But they are not threatening.
I don't know what is best at here, maybe I played c5. I think c5 is flexible move.
At some point, Nc6 or Bc6 block c pawn.
For example, Rc8 Bc6.

IMO 14... Rac8 is the beginning of your problems. It’s not a bad move on its own, but your follow-ups show you’re on the wrong track. c5-c4 favors white because it gives the first player a strong center, as well as a semi-open b-file.

In the reverse-Stonewall structure after 14. c3, I’d say the position is balanced. Black has a bad bishop, which is compensated by his slight lead in development. Black should either trade his bishop for white’s superior one, or try to open up the position (to utilize his lead in development).
For the former idea, 14... a5 intending Bb7-a6 is a safe move. The position is almost equal after a bishop swap.
For the later, 14... Qe7 is an interesting try, with f7-f6 and e6-e5 in mind. Note that white is unwilling to open up black’s LSB with c3-c4.

I didn't like your Pawn push from c5 to c4. It released all the tension in the center, and didn't seem to gain much in return.

Was there something wrong with keeping that Pawn on c5 and doubling your Rooks behind it? After Rc7 and Rfc8, you will always be on the verge of threatening to trade cxd4 opening the c-file at an opportune moment, and the maneuver also clears f8 as a maneuvering square for your Knight. You might even increase the pressure in the center by Qe7 and f6 (to threaten the push e6-e5).

Thanks inkspirit and rhr. Interesting to see that I analysed 14...a5 and in the only line hat I analysed I had an excellent position. However, in this line the white Queen was allowed to come in my position, and I tried to find another line where this was not possible, and this was just a mistake, of course. ...a5 is a move often played in such kind of positions to exchange bishops, and white would not be able to avoid the exchange. What a pity that I didn’t go for this!

I think 14...Rac8 is a good move, but the follow-up c4 is bad. Rac8 was played with the wrong idea. The move itself is still good. I don't understand how you can think that is an inaccuracy. Putting rooks on the c-file is a very common idea in this kind of structure.

To put a rook on the c file is a common procedure in defences whrere black goes for ...d5, and this is perhaps the reason why I played it. However, if we see what happened in the game, it seems that ...a5 is what the position is crying for.  This moves has many purposes. First of course the exchange of a bad bishop against a good one, one of the most important strategic ideas when black goes for d5 /e6 (a5... is also often played in the French). And  it prevents white to do what he did in the game. It is by far the move that I analysed most (as you can see in the game), and it is now difficult for me to understand why I didn’t go for it. It would a very different game, more pleasant for black. 

c5 is good in both positions and the most natural move to play. It can easily turn into a similar pawn-structure. 11...c5 12 d4 is a possible continuation. If you don't beleive me, analysis please.

 

We can't conclude anything from the game, because c4 was played. That idea does seem to simplify the position, but black isn't worse to start with. I would prefer black on move 14.

I will start the engine and check the moves.

The problem is that the rook cannot do anything on c8. White is happy to see black play on the c-file with cxd4, since white’s superior bishop will give him a long-term edge in the endgame (after rooks are traded). Again, 14... Rac8 is not a bad move that does immediate harm, but it fails to deal with black’s long-term weakness (LSB) or make use of his lead in development.

You said that “putting rooks on the c-file is a very common idea in this kind of [Stonewall] structure”. Typically the Stonewall side (let’s call him Side B for concision) has a bad bishop, which means that opening up c-file would give Side A (the opponent of Side B) a comfortable position. That’s why Side A usually deploys a rook on c-file, and Side B does the same to guard c7(c2)-square.

However, in this game Side B (white) has a good bishop, while Side A (black) has a bad one. In this case it favors Side B if Side A opens up the c-file. This is why 14... Rac8 is kind of a useless move. Neither side is going to play along the c-file.

Edit: grammar.