Allow me to venture into a slightly un-politically correct analogy. Back, many years ago, when I was just a child there was a children’s song with a colorful and history: “Ten Little Indians” whose original title was: “Ten Little Injuns”. I have often used the phrase “10 little idiots” to describe my fingers. I complete the analogy with the idea that the 10 little idiots were controlled by the Chief Idiot. As I have worked my way through the rehabilitation of my left hand I am seeing the legitimacy of this idea. The initial surgery was followed by a very difficult staph infection which necessitated two additional operations. My left hand was in pretty bad shape when I began my occupational therapy. It wasn’t until about 5 weeks after the surgery before I began to tentatively play the piano again. I had about 40% range of motion in my fingers and probably about 30% in my thumb. In terms of strength my guess is my left hand was 20% of my right hand.
After a few days of 15 – 30 minutes of playing I had be able to move my hand enough to play Bach’s inventions and simple Haydn Sonatas. Once I felt comfortable enough with the physical act of playing (learning where the limits of range of motion were mostly and what motions were painful) I began to turn my attention to musical expression. To my great joy I found that even with this sad excuse of a hand I had no difficulty in doing whatever I wanted to do expressively. Granted speed was and is still limited (but getting better every day) my ability to express music did not reside in my little idiots, it was all up to the chief.
You don’t have to train the fingers; you have to train your mind.
The ability to imagine YOUR fingers, wrists, and arms doing something is the critical issue. Just because you heard someone else play something means nothing if you cannot imagine your own fingers doing the same thing.
I have found one of the best exercises to learn chord voicing is to split the chord between the hands. Play the important note in the right hand and everything else in the left. Work at it until you have the color you want and listen very carefully to the dynamic level of each note. Now repeat the chord with just one hand. Now that you have heard your hands playing the balance you wanted, even though it took two hands, you will arrive at needed physical solution to your musical dilemma. It wasn’t because you drilled your hands into submission, but rather you taught yourself the proper amounts of weight to put into each note and even though the lesson was taught with two hands, it provides enough information to make a one handed effort much more successful.