Some pianists, (many well-known concert artists, in fact) find playing from memory easy, and some find it very difficult. The pointers in this article, from Pianist magazine, may help.
This article appeared in Pianist (the magazine) June-July 2003
the image is from Ask A Biologist web site
Can your experts give any tips on how to learn pieces from memory? Is there a technique (other than playing pieces over and over)? I'm breathless with admiration when an artist plays a whole concerto from memory, but I would value hints on memorising short pieces.
John Ellis, London
Some pianists, (many well-known concert artists, in fact) find playing from memory easy, and some find it very difficult. However, the following pointers may help:
Take each bar, or a few notes of a phrase, one hand at a time. Play them with the music in front of you a few times so that your fingers begin to feel where they should go. Try listening to the sounds you are playing (hum the tune in your head if that helps) then gradually move your eyes away from the printed score, until you can pick out most of the notes correctly. You can also play a game with yourself by moving the score further and further away, so that it becomes increasingly more difficult to retrieve the score.
Once you can play a few notes in one hand, try the notes in the other. When you led comfortable with both hands, separately, try both together. Do this in piecemeal fashion, building up blocks of notes, then bars (one bar then two. and so on). and then longer phrases. Test yourself the next day by trying to remember what you did the day before.
Memory techniques differ greatly. Some pianists rely on what they call muscular memory. Others rely on the sound, while some have a very good visual memory which makes it possible to see the music clearly as they play. And of course, many accomplished pianists have an excellent understanding of how the music is put together both harmonically and melodically.
The best advice is to keep persevering, bit by bit. Go back to what you did a day or two before and test yourself to see how much you can remember. You may be surprised by how much you can recall.
You can always try practising away from the piano too (on a train or bus, for instance), with the score beside you, trying to listen to the music in your head. You can also try the technique of playing above the surface of the keys.
Finally, don't think that because many pianists play from memory that they are any better at it than you. It's just that they have trained themselves, and for a much longer period of time. Unfortunately, as with all great art, nothing that appears easy is easy.
See also this external link: Memorising music