Could it be that in order to become a grandmaster, your brain should differentiate functionally or even structurally from the majority of club players, thus it may as well be highly improbable for a trainer to get a grandmaster out of a wannabe whose brain is mediocre for the standards of the game?

Just look at this:

(..) Chess titans have anywhere from 20,000 to 100,000 configurations of pieces, or patterns, committed to memory. They are able to quickly pull relevant information from this mammoth database. With a mere glance, a grandmaster can then figure out how the configuration in front of him is likely to play itself out.

Amateurs, by contrast, use short-term memory while playing chess. When they take in new information, it stays in the "small hard drive" of working memory without passing over into the "zip drive" of long-term memory. "Amateurs are overwriting things they've already learned," says Amidzic. "Can you imagine how frustrating that is!"

Amidzic's research suggests that chess whizzes are born with the tendency to process chess more through their frontal and parietal cortices, the areas thought to be responsible for long-term memory. Players whose medial temporal lobes are activated more will be consigned to mediocrity. He hasn't yet been able to follow children over time to see if their processing ratio of frontal-and-parietal cortices to medial temporal lobes indeed remains stable, but his retrospective analyses of older players show that their ratio corresponds to their highest historical chess rating, as would be expected if the ratio truly predicts chess performance. And he doesn't think that gender influences this proclivity. He had scanned the brain of a 22-year-old female chess beginner and found her ratio to be far above average. If she sets her mind to it, Amidzic believes, the young woman has the potential to become a master-level player.

Amidzic's own chess-processing ratio, on the other hand, is about 50-50. "I'm the Salieri of the chess world," he says. "I'm talented enough to admire and also to know what I will not achieve. It's better to be ordinary and not know." (...)

http://www.psychologytoday.com/articles/200506/the-grandmaster-experiment

yes the trick is you have to beat your head in with a club as hard as you can, hopefully enough to give yourself a brain altering concussion. repeat until you are a grandmaster.

Grand Masters are normal people with the capacity to play chess very well. Sciencist are good for math but maybe they aren't for football or tennis, and tennis players maybe aren't good for physics. Each one have a capacity, nobody is an alien or a Lex Luthor. One day, around his 50's this capacities begin to fade like in a normal people...

Do grandmasters have different brains?

Yes. If they all had the same brain, they would have to take turns thinking.

Grandmasters don't have brains. They're really chess computers with a robot body attached to them. Top level chess is just an illusion, made by the elite who wants you to think that humans could become good at chess and therefore you will invest time and money in that develish game instead of becoming a conspiracy nut who knows reality!!!

Don't we all?  Or do we?

I wonder if there would there be difference in the pattern of brain activity if the analysis was done on blitz players ? I would imagine the time issue might cause different circuits to light up - those able to make quicker decisions.