Solutions for strategic exercises - Part 1/2

While presenting the solutions for the strategic exercises that was published a couple of days ago I will try to go with a principle of simplicity.
However the position which you can see on the first diagram demands a very deep analysis.
I will leave some points where the  curious reader can go further by themselves and publish the solution in the two parts.
The second part will contain the solution for the position on this diagram. 
The first part are the solution on subjects, weaknesses and prophylactic thinking.

Weaknesses...

IM Bejtovic Jasmin E2406 - Tari Aryan E2293
Copenhagen Chess Challenge 2013

I played against young Norwegian player who is in the moment of writing these lines already on the same Elo as me.
Anyway, his opening was not so impressive, and I found the good way to exploit it.

9. b4!

This is the right move.
I managed to fix his structure on the queen side, to make a good place for my bishop on b2, and the most important to make an outpost square on a5. This is the most weak square in the Black position, and if my knight goes there I will put a lot of pressure on his bishop on b7 and weak square c6.

9...0-0
10. Nb3

We can stop here and conclude that White is slightly better.

IM Bejtovic Jasmin E2406 - Bank Pelle E2246
Sondex Cup 2013

In this example we can see how easy everything can go wrong if one side is playing with the right and deep plan, and other side is playing natural, "I am doing nothing" moves.
The real weakness is d6, but do not forget b6 square and b7 pawn.

23. Ra4!

My idea is to put my rook on b6 as from there it will attack the both weaknesses, his b7 and d6 pawns.
Later on I can bring my bishop on a3 and knight on e4. He did not reacted well, and the game went...

23...Rc8
24. Ba3, Ke7
25. Rb4, Rc7
26. Rb6

White is clearly better, I would dare to say that my position is already winning at this point.
In the position on the diagram, I was only slightly better. Black made no obvious mistakes and is close to losing, only four moves later. 

Prophylactic thinking...

IM Bejtovic Jasmin 2406 - IM Bromann Thorbjorn 2369

Sondex Cup 2013

The positions on the next two diagrams are from the same game. I have a very pleasant advantage, almost winning.
Before I start to work with his weaknesses on the king side, by putting one more attacking piece around his king with h4-h5 I need to prevent him doing his defencive idea of Qe7-Nd7-Nf8.

35. a4?!

Before my operations on the king side, I decided to close the queen side (just to prevent some counterplay there).
The right move was:

35. Qg5!

In order to prevent 25...Qe7. It will lose now because of mate on f8.
Anyway, I will just push my h-pawn to h5, put my rook on f6 and everything is over.
Black has no counterplay.

Some moves later, a very similar situation.
I did some progress with my h pawn, and closing the queen side.
On the other hand, he is only one move from deliberating Nf8.
Prophylactic thinking is needed again!
This time the whole idea is a bit more complex.

38. Qg5?!

I made mistake again, and even later in the endgame I had some good chances but ruined them all.
The right move was:

38. Qh6!

This is already very hard to see.

38...Nf8
39. Ng5!

Attacking the new weakness on f7.
As the checks on the e-file gives nothing, the best chance for Black is to play for a fortress.

39...Rd8
40. Rf7, Qxf7
41. Nxf7, Kxf7

My feeling is that this position can not be a fortress.
It really looks that everything is protected and that Black can only move his king, but I can put my pawn on g5 and check him on f6. In that scenario I would win the seventh rank and put my queen on c7.
In that case it will not be possible to play Nd7 as the pawn on d6 would fall.
I am sure that Black can put more resistance on this plan, but somehow I do not believe in the fortress here.
This position demands further analysis.
This is why I think that the second position is much harder to solve then the first. It is not easy to make decision if this position is fortress or not.

To be continued...