The Ultimate Zugzwang & Triangulation Puzzle

This is the most beautiful chess puzzle I have ever seen. It covers the vital aspects and the absolute beauty of chess which is incorporated in the training of a proper dedicated chess player. So, as the name suggests

"The Ultimate Zugzwang & Triangulation Puzzle".

As we proceed to solve this puzzle the reason of this name will be unfold by itself. But before that we should first understand how to approach a chess puzzle/a chess position and that is because we are generally habitual with the practice of viewing things only from our perspective i.e., we only think about our moves and not the opponents move. Instead we should think of the best possible moves for both sides regardless of what colour side we are on. Hence, keeping these things in our mind let's jump onto the chess position. 

So, here's the position and It's white to play!

You can try to solve this on your own if you want. Otherwise here's the complete move by move breakdown of this beautiful chess position. 

First we have to see the positioning of pieces of both sides and then evaluate what is actually happening here. 

So materially , white has a rook and a bishop for black's queen with 3 pawns and a knight each. But positionally, white has to be completely better here for the following reasons:

1. White's pawns are much better as compared to Black's because black's pawns are blockaded. 

2. White's pieces are extremely active surrounding the black king in a mating net where 1 check will end up into a checkmate whereas white king is safe on b3.

3. Black's pieces are highly restricted as you can see the knight on a7 literally have no squares to go to , all the black pawns can't move. 

Right now it's white to play and white's rook on e4 is attacked by black's queen on a8. 

So white just moves it back one square safely , which also prevents Qf3 check.

Now, what can black play?

As we discussed earlier black's knight, all the 3 pawns including the king don't even have a move. So it's obvious that it has to be a 'queen move'.

But now the question is, where will the black queen move ?

Black has a serious problem with his king and the problem is that white's knight is willing to give a check either from the d5 square or the g8 square and that will be checkmate as black king is in a complete mating net. Hence, Black queen has to move in such a way that it controls both the d5 and the g8 square. This can be only done via the g2 square so, Blacks plays Qg2. 

Now white wants to disrupt the black queens control from either one of the squares (i.e., d5 or g8) to deliver mate. So, white plays Bg4 disrupting the black queen's control from the g8 square.

Now what can black play?

White is threatening Ng8# and black can't take the bishop on g4 because then Nd5+ would be mate , Hence, Black queen once again has to keep an eye on the two key squares (.i.e. d5 & g8) . So, Black plays Qa8 still controlling both the key squares firmly. 

Since, Blacks moves are forced and limited white makes a waiting move with Re5.

Now, Blacks decisions get even more tougher and limited as the queen now cannot go to g2 because there is a bishop on g4 blocking the access of the g8 square so, black has to find another way of controlling both the d5 and the g8 squares. Hence, Black plays Qd8 again maintaining the control of the two crucial squares. 

Now white responds with Bd7 again disrupting the black queen's control from the d5 square . And threatening Nd5# noting black can't take the Knight on e7 because then Rf5+ would be mate. 

So once again black has the only choice to just go back to a8 in order to control the d5 and the g8 squares.  
Black plays Qa8. 

Now white plays this insanely brilliant move Re4.

Now what's insane about this move ??

So, if you look at the current position that we have reached it is the same position that we had in the start of this puzzle but , the only difference is that now it's "Black to move". Whereas at the start it was "White to move". 

So it was an ultimate Triangulation (which is a very important concept in chess).

But you might wonder, What did we achieve with that..???. What's so insane about it ??.......................................................

Now , if you look at the position. It's Black to move and as we know that black has to control the 2 crucial squares i.e., the d5 & the g8 squares in order to avoid checkmate . But, as of now that we have played Re4 , black no-longer can do that , because the rook on e4 blocks the Queen's access to the g2 square from where it would have controlled the d5 and the g8 square.

Hence, finally with that ''Ultimate Triangulation of white'',.... Black went into an ''Ultimate Zugzwang''and now it's Mate in 1 in the next move no matter what black does because black has to give up the control of either of the one square (i.e. the d5 & the g8).