...but I just didn't see it?

My game on FICS this morning had couple of knocks and turns but in the end I missed a mate which would have resulted on defeat or draw if my opponent would have been more careful.

My theory goes if I try to verbalise the ideas - maybe next time instead of my mind going blank I would maybe recollect the idea.

The thing was I was short on time. I was trying to calculate and did saw two halfmoves ahead but failed to asses the position after that.

My opponent was clearly better and fumbled with 27.g3??



I did found 27...Rxb2!

White king has nowhere else to go to but 28.Ka4.



Here I spent three minutes and 17 seconds from 20 minutes I had for all for these moves and now I was running on few minutes.

In my mind I did see 28...Nc5+ 29.Ka4



But then I did not see the next move. I gathered I need another rook.

All in all I did not succeed to visualize where I could mate exactly and how did I could mate.

So.

29...Rd6 and white has nothing to prevent 30...Ra6#

So I saw Nc5+ but played 28...Ka8? and here the game is draw. Fortunately my opponent didn't pull it off.

I think I was trying to get my rook to a6 using four moves or rather get two rooks restricting white king.

I am not sure how to avoid such blank moments. Instead of vague idea I would need crystallized moves.

One thing is maybe have a mind fully working. I'm bit tired at the moment.