I’m playing a folk song on my pedal harp, and the music has two parallel wiggly lines in one measure in the treble clef that I’m assuming mean a gliss with two fingers.
>They both tell you how it’s done and although one harp site believes it is taught by Alfredo Ortiz the other is not sure where it originated from.
If I understand what you’re saying, two fingered glisses have been part of basic harp technique for many, many years. Perhaps as far back as the late 18th century, although glisses were not used so much back then.