Question: What is this "H" symbol above the staff in my copy of the string quartet transcription of the Art of Fugue?
Background:I play guitar but recently realized that most string instrument parts are pretty easy to play on guitar and I'm learning to read so I bought a transcription of the Art of Fugue by Bach. I'm guessing that the "H" symbol might be bow-instrument related but I can't find anything on google or in lists of musical symbols....