Question: After 56...Nxf4, find the only losing move for White that doesn't involve putting the queen or bishop en prise?

I also agree, kiril's King was not under tremendous pressure. It was his Queen! And when kiril saw he was about to lose his queen (and his king, of course, next), he resigned!

Perfidious, your comment smacks of ignorance of the pressure of playing competitively. Chess is a test of nerves, too, as Bronstein said. How would one explain Georgiev's blunder if he was not feeling pressured playing an imbalanced position? And perfidious, I can assure you that I can play and annotate at a decent level, so don't rush on the fanboy tag.

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Basically, he could have given up his Queen for a winning position, but, usually, players would rather retain it, as So did. He blundered with 32. Ne2 and allowed a mate in two. But is this mainly a result of relaxing his guard? GM Giri was throwing his pieces at him before the blunder, didn't the ferocious, if unsound, attack play a role in making So crack?

I read your posts that is why I am arguing your point about "pressure" or "pleasure" at a winning position (which I gave as another explanation to losing or sometimes drawing in a non-pressure situation but I don't think it applies here). I watched this game live in the internet, with the times for both players displayed, and the position. Georgiev started playing on his opponent's time, a bad mistake from a veteran player (you can see that because his time actually started to increase with the 30 second increments). Playing tournament chess you only do that if you are a.) confident in your winning position and b.) to pressure your opponent in time trouble into a mistake. It backfired because he was the one who didn't properly calculate a tactical sequence, choosing the only losing move.

Now let's parse your opening statement above, with emphasis on the words I will try to argue against: "all blunders are blunders <regardless of the circumstance> that is how we get better trying to learn."

I don't agree with <disregarding the circumstances>. How does one play in time trouble (yours or the opponent's), analyze particular types of position, and react against the opponent's movements and expressions also offer valuable insights for improving one's play. Therefore, I believe, knowing after a game that a certain move was a blunder isn't enough. You must try to figure out why you made it. This is what I was attempting for this game on the onset, and because I didn't watch the game live, you are probably correct in saying that <Georgiev started playing on his opponent's time, a bad mistake from a veteran player (you can see that because his time actually started to increase with the 30 second increments).> Still, however, it doesn't totally negate the fact that Georgiev reactions were based on factors related to the game (opponent's time trouble, better position), so, directly or indirectly, he was 'pressured' until he made the losing move. One also has to consider the fact that in a hard-fought chess game such as this, the pressure builds up from the beginning until it is terminated by the outcome of the game. It doesn't make sense to me that a veteran GM, with more time on his clock and a winning position, would lose through a single, seemingly obvious (in fact, it hardly requires deep calculation), error.