The problem with theorizing about Fischer vs. Carlsen is:
Fischer was hugely insecure. If Fischer in peak form was to face Carlsen at his peak, Fischer would have found an endless string of excuses for avoiding playing him.
Strange how as time moves on all the negatives about the man are sloughed off until all that remains is positive and fanciful.
Fischer had a brilliant talent but is was embedded in a deeply flawed individual.
bean_Fischer
My guess is that 20...Qa5 would be met with 21 b3 and 22Bh5 would be difficult to meet, though possible.
The problem with theorizing about Fischer vs. Carlsen is:
Fischer was hugely insecure. If Fischer in peak form was to face Carlsen at his peak, Fischer would have found an endless string of excuses for avoiding playing him.
Strange how as time moves on all the negatives about the man are sloughed off until all that remains is positive and fanciful.
Fischer had a brilliant talent but is was embedded in a deeply flawed individual.
Fischer was never insecure, he had honor that is a difference!!!
the kafka example a very good one.
See Carlsen is really great, just perfect technique like a really good writer who is in the command of the english language better than anyone.
but he is missing the great inspiration of a Kafka or better a Fischer.
I never said Carlsen was bad, that was not my intention, maybe technique wise he will be the best ever ome day who knows.
but the magical god given inspiration of a Fischer, he never will get. Its lost on him
thats what they said about steinitz...they didn't know what he was doing
carlsen is playing against computer theory...he is laying the groundwork, the foundation that later generation players can use to create chess pyrotechnics...
you cannot play chess like fishcer did in this day and age and expect to be number one...
everything is hyper analysed...
but someone forgot to tell ivanchuk
Everyone is welcomed to make a prediction about Sinquefield Cup 2017! 
Here:
https://goo.gl/forms/6RJrsThyUDnEB8Cv1
As far as I can make out, black's problem is that he is already losing when he makes the choice between Qa5 and Ra6. Ra6 is well motivated - to shift the white queen from a crushing square - but it is too late. More specifically, 20. ... Qa5 21. b4! shows that the white queen has another useful role.
Why not 20. ... Qa5?