Thanks, Saul. I assume the nut is the guard at the bottom point of the string where it enters the soundboard, and that you mean the soundboard must have a high arch. Oberthuer describes the effect as a portamento, which can mean a shift of pitch toward the next note, as with fingerboard instruments. His example shows stepwise motion, but both up and down, and the pitch shift could only be up, as it tightens the string tension. Seems similar to the effect of a mandolin. For notation he suggests the carot mark, like the accent, but it appears there is no standard notation or abbreviation. I inherited his manual from my mom, a professional harpist in Seattle and my first teacher. She never told me about the manual. Maybe she never used it herself.
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