This approach does seem to work a bit, of course. However perhaps there is a better way. Sometimes the hand movements are such that the eyes must leave the score and watch the keys, and actual notes must be recalled. I had regarded this as counter-productive, but my reading is starting to suggest that this is the way to go, in that pieces should be structurally memorized, and during play the mind should be active in recalling this structure and directing the hands through the composition. This would make the problem of occupying the mind while relying on automatically reading the score and playing a composition through hand memory moot.So perhaps my current way is bad because it seeks to play a piece automatically, with no intellectual involvement, which in the end leads nowhere really.
Today I tried something different. I just worked on one piece, away in a manger, which I find fairly difficult. I divided it into 4 overlapping sections, played each section HS, then HT, then the whole piece HT. I had some trouble with fingering, and played the whole piece HS/HT alternatively for a while. I spent about 4 hours on it. At the end I was playing at an adequate tempo and technique, but with a few fingering problems with the chord changes still.Although I tried to memorize it, I do not believe I did. My short term memory is shot though, those variable names just do not stick like they used to. The question I have to ask myself, if I spent 4 hours just playing the piece through, how would I have gone? The answer is, probably terribly, my fingers would have tied up in knots after hour 1, so the experiment is a qualified success.