I really struggle with memorising piano music. I can memorise flute/ single-line music but, despite trying lots of strategies for memorising piano pieces, the most I can usually manage is a couple of bars. There are only 2 notable exceptions:- The Maple Leaf rag and a grade 6 piece from a few years back (Vals poetico- Granados).
Over the last couple of weeks some of my piano students have been working on 1 of the AB grade pieces and although I have demonstrated an occasional bar to them I haven't played it completely through more than a handful of times. However in the lessons we have studied the patterns, harmonies and fingerings. Yesterday, while idly filling in the few minutes between pupils, I amazed myself by playing it from memory not just once but several times and on further experimenting found I could pick up & play from any point. Which might not sound much to people who can easily memorise but was quite an achievement for me especially as I hadn't played it over & over again but had simply spent a lot of lesson-time looking at & thinking about it.