HINT: Slow and waiting move from the rook is all it takes! ;-)

I'm kind of new to chess puzzles, but... wouldn't this make it winnable for Black? I mean, White can either trade the Knights after Nc6 or run away with theirs, sacrificing their checkmate in return...

Prativa, that variation leads to 2 moves checkmate, 3.Nd5+ Kf5 4.Re5#

Analyse before posting next time

And dont put the puzzle in the middle of your sentence, that looks stupid xD

Please stop spoiling this awesome puzzle with your crap

Tough one alright !  I couldn't make sense of black's first move until it occured to me that this is about Zugzwang - he's forced to make a disadvantageous move. After all, black's king is blocked & either of the two black knight moves results in immediate mate by 2.Nd5 or 2.Ng8.

 As amcgee3 points out, black's queen must attack the d5/g8 sqares & can only do that from a8, g2 or d8, hence the rather strange triangulation.

I got the early moves by guesswork or trial & error - did anyone get this in one ?

Satisfyingly difficult - not one for beginners.

"did anyone get this in one ?"

Probably not! This is way too hard to get it at first try.

I inserted a hint just to help a little bit since it's too hard!

Actualy is not at all mate in 6 move, if 2.Bg4 even mate for white:

2.Ng8#

Notice the solution has 1...Qg2 not h1.

sorry my mistake

But i observe another issue. From beginig here after 1.Re3... is an zugzwang. All black moves prevent the mate, without any other options.

sweet! took me 30+ minutes to crack

Yes, if you pay attention, you'll notice that Black Queen is basically trying to protect the d5 and g8 squares from the Knight's mate. And notice that in the 5th move it returns to the start position, but now Black has to move, not White. And even if the black knight moves in the 5th move by Black, it would block either the d5 or g8 squares. So the white knight can eventually checkmate on the d5 or g8 squares! ;-)

Yes, the d5 and g8 squares are always protected.

...

What about 2...Qxg4 ?

Am i missing something? Why not 2...Qxg4?

Sure, it becomes a mate in 4... I guess i'm used to problems that want exactly a mate in 6.