|Who needs metaphors when you have reality?|
In this blog post, the author discusses a technique that I'd forgotten about since my piano years: memorizing hands separately. That, to me, is even more unmusical than memorizing individual voices in a fugue.
I'll ask again as I've asked numerous times in this blog: What is the ultimate goal of your memorization work? For many memorizing musicians, there is a strong degree of impatience with the process, especially with a conservatory mentality that's not always working in the best interest of the music.
If one is memorizing hands separately, one is truly establishing tactile memory. It can't really be aural memory, because one isn't actually hearing how the piece will sound. It can't be visual memory, because one is presumably not working with the score away from the instrument. Ultimately, this type of memory will fail, if not in performance then in the amount of time it takes to bring a piece back to memory.
As the parable says, a house built on sand will fall under stress. If you're going to make the effort to memorize your music, you really should do it in a way that ensures lasting quality.