question: I don’t know what those dashes on the notes are in Bowing variation 6 of Wholfahrt op.45, no.49.
beams and flags of the notes
First of all, I’d like you to know the term beam, which is the line to connect more than two 8th notes or shorter notes (16th notes, 32nd notes, etc).
As you can see above, one beam connects 8th notes, two beams connect 16th notes, and three beams connects 32nd notes. The number of beams are the same as the number of flags.
slashes on the stems help representing the number of beams
Let’s go back to the slashes on the stems. In this case of Wohlfahrt no.49 variation 6, notes are written as connected 8th notes and one slash is added on each note.
These slashes on the stems (your expression of “dashes”) represent additional beams, so that you play each note as the notes which has two beams = 16th notes. You need to play it as:
It is not as complicated as you think. Thank you for your question. I look forward to listening your wonderful playing at your next lesson!