I'm an organist, and I think these problems become even more severe when playing the organ. Every instrument is different, both because the organ itself is usu

I'm an organist, and I think these problems become even more severe when playing the organ. Every instrument is different, both because the organ itself is usually unique and because the room will be different. Some organs are large enough that it's best to think of the instrument as the organ plus the room (the strings and the hollow body, respectively, if we thought of it like a violin). Anyway, if the acoustic is dry and you want to play legato, for example, you can end up choosing to use a fair number of finger substitutions and to use thumbing [1] in order to avoid some gaps between notes – which goes to show that the choice is both a function of artistic interpretation as well as locale, on top of comfort or efficiency. I believe (but I may be misremembering) that in some historical practices, as well, there are fingering practices deliberately chosen so as to naturally create phrasing (e.g. try playing a scale as evenly as possible with just fingers 2 and 3 and you will inescapably get some rhythm). [1] A technique where you smoothly move to an adjacent note with your thumb by see-sawing between the knuckle and fingertip, which works because key velocity matters much less than on a piano (and for electric action, not at all). In fact, you can smoothly play an entire scale this way with just your thumb. "Thumbing down" can also refer to playing notes on a lower manual (keyboard) with your thumb while the rest of your fingers play on an upper manual.