Why does this happen? Three reasons. (1) You are playing on an unfamiliar piano, one you haven't played since last week. (2) You want to do a good job. Murphy's Law says you won't! (3) It is a stressful situation. Not only playing the different piano makes it stressful, but also your teacher's presence.
The solution? You won't be surprised to read that I advise you to play more slowly at the lesson than you feel you can control the piece. This slower tempo makes up for the added stress of the situation, and you are bound to play more accurately for your teacher than if you select the tempo you used at home.
If you don't believe me, try it once and see.
copyright 1996, Martha Beth Lewis, Ph.D.
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