In the WTC (Das Wohltemperierte Klavier) there can be some intervals that are quite awkward to play. In the first fugue I find a lot of weird intervals that do not flow under the fingers and it requires a repositioning of the hand, unlike most of the fugue where virtually all the notes just fall under the current position. Part of this is due to me just choosing the wrong fingerings early on but some are simply part of the scores.
For example, in measure 17.5L There is an octave span D to D and the top D goes to E and walks down. This clearly requires using the thumb if one is to hold the lower D or one could, if they can reach it, hold the top D with the index finger (very awkward).
In measure 19.5 the exact same motive exists but he pushes the E D C walk down into the right hand.
Now, I can manage these easily using the thumb but for people with small hands I don't see how they can properly play these without releasing the lower note to free them up.
I find a lot of issues like this in Bach where it just does not make sense fingering wise. While I can manage it, there just seems to be stumbling points that do not flow naturally (and I do not know if it's my fault or just part of the music). Usually if I figure out an easier way to play it then it causes problems before or after getting in to it so the problem really is not eliminated.
I feel this is just the nature of the counterpoint and fingering difficulties are accepted. The piece is played slow enough that these things can be managed...
But I wonder how smaller hands deal with these problems? If there are certain excepted solutions then I imagine they could be applied to larger hands to make things easier.
I realize that the keyboards of the past were smaller so many of these issues did not exist, but some clearly did (an octave, for example, with the melody leaping up requires the thumb to play consecutive notes and this cannot be done with legato, if the lowest note is held with the pinky).
Has someone created a list of accepted modifications to make certain figures easier to play? (e.g., one can shorten the bass note (pinky) to remove the stretch if it does not interfere musically)