Dark square strategy

The game I will show today is, in strategical terms, my best game in this year.
My opponent was FIDE master from Bosnia&Herzegovina that already passed his best chess years, but still manage to keep his elo around 2200.
The commentary of this game will not be about concrete variations, except in some cases when there are some beauty in the variations.
I will focus on strategical parts of the game, and try to explain what it means to make a plan for the whole game.

As you can see, we played very odd variation in The English opening, and my opponent decided to give his dark-squared bishop in order to get quick development and free play for his pieces.
His main objective is to play on the king side.
In the matter of fact, I think that he has good prospects to achieve an attack there, so I hesitated to castle short.
To castle long in this position was not an realistic solution.
I understood that my opening play was not very impressive.
In order to keep some chances to play for a win later on, I have to keep some advantages in my position, even if the final evaluation of the position is not in my advantage.

So the question is what is the advantage of my position?
Well, I have a bishop pair, and that means that my dark squared bishop does not have the opponent. I need to achieve some sort of static position in which I would be able to open the long diagonal.
On the other hand the plan of my opponent would be to open up the position.
It sounds strange that the side with the bishop pair has to keep the position static, while the side who play against the bishop pair has to open up the position.
But, do not forget, the advantage of bishop pair is not the main characteristic of this position.
Black´s development is more important.
In this position, as you can see in the chessviewer, my opponent played some neutral moves which does not fit to the demands of the position, and soon we reached the following position:

All right, we have the position from introduction.
Black is on move.
The only reasonable move here is d6-d5.
Black needs to close the diagonal for my bishop.
I am not sure who is better in that position, as White has some ideas to play for (for example Nc4-Ne5 can be one of them, or simple play on c-file).
Black needs to keep his control over d5, but what would be the next step?
So the general conclusion is that any move by Black, without d6-d5 would be positional mistake.


Black played:

14...a5?

The question now is: Is this move only weak for above mentioned reasons, or there is something else?
Think about it, try to imagine the situation that you are White, and you need to make a plan in the game.
The main problem of White position is the position of his king.
There are no safe place on the board for White king.
After a7-a5 Black lost the possibility to play a7-a6 and open up the a-file in the case that White castles long.
I got the possibility to castle long, and to play for h3-g4 break.

Later in the game we reached the following position. I managed to play f2-f4 and what would happen if he took on f3, is explained in the commentary.
Now, I can play with my knight on d4, and I bet that the huge majority of the readers would make that move.
It is such a natural move.
later on White can jump on c6, and who knows, maybe is that quite reasonable way to play.
Anyway, in Neum I was in good form, and I transferred my knight on h2, which is very clean and strategical solution.
After I played g3-g4 Black´s position fall as the house made of cards.