Forgive me if this is an old argument, as moot as "which came first, the chicken or the egg." I've scanned the first two pages or so, and I don't see anything like it. So, here we go. I've been playing for about four years now, and my teacher has always encouraged me to curve my hands when I play. This feels very comfortable and natural to me, and I feel I have the most control when I approach the keys like this. However, I'd been having a lot of difficulty with certain quick passages. I recently attended a masterclass and the artist showed me how I could play a lot more efficiently through alberti bass passages with flat fingers. When I try this, it seems to accomplish the goal more effectively, especially with softer playing because I don't lift my fingers off of the keys when they are coming back up. What do you all think? Should you curve in certain instances and flatten out your hand in others? Thanks again.