Today I was playing an exercise, mainly playing a scale fragment which
consisted of almost all black keys with only a couple of white notes, and I was
playing this "deep" towards the back of the fallboard.

There are a couple of white notes in this, and of course I had to use a thumb
under motion to hoist the hand to a new five finger position. Nothing wrong
with that, but since I was playing deep, the thumb going under landed between
two black notes. I was playing real deep. I was thinking this was a BAD move,
and that I should at least avoid getting the thumb caught between the black
notes when making a thumb under motion. But I mean, it can fit in there,
because the digit is slender enough.

Anyway, is there any benefit to practicing or getting used to that..especially
if you are playing in the upper region of the keyboard? That is, if you are
mostly playing between the blacks, and when making a thumb under motion to a
white note, would you work on it so that it thumb lands on this white note
BETWEEN the black keys, instead of the thumb shifting down this white note
BELOW the blacks? Naturally the thumb will land below the black if you`re NOT
playing too deep on the black keys, but is there a benefit to making an effort
to cross under between two black keys in the way I describe. Just to keep
things even as far as front to back shifts go. Especially if most of the
passage consists of mainly black notes with only a couple of white notes you`d
cross a thumb under to? What is your opinion on this? I`m guessing it`s a
bad idea, but maybe somebody else has better wisdom to offer.

thanks,

First, I don`t think it`s a good idea to play that high on the keys. It`s REALLY difficult to control.

There is nothing wrong with the thumb-under technique. I would prefer it in this chord: (low to high) Ab Bb C Db E, fingering 2 3 1 4 5. I find that much more comfortable than 12345, which makes you have to play high on the fallboard.

The thumb-between-black-keys would be a bad idea IMHO, especially with fat fast chords (Rach 3/Mvt. 1/Cadenza Pianoforte - transpose that up a m2).

But whatever. Do whatever you think works. It`s not a rule.

sounds like someone has already played rach3....transposed?!

I`m just using that as an example.

thanks for the reply, Harvey.