Great spontanious pianist, in practice, build up a palette of colouristic, rhythmic, and dynamic possibilities for each phrase.Of course, many wouldn't work, but many would, and it's often hard to choose which one to go for in a performance, so they don't choose and leave it to the moment...and sometimes they will do a thing they hadn't even prepared in practice, but this is more dangerous.The difficulty of this is to have a coherent and convincing 'whole' interpretation whilst also having loose and flexible moments to play around and have fun.Keeping a sense of the forrest while you're working on one tree
And how could a pianist go about creating the illusion of freshness?
Great music never dies as long as it stays alive in the heart's of it's listeners.
Argercih. A prime example of "spontanious" playing.
if you play too fast - the ears can't take it. if you play too slowly - it's boring.