This is from the playing of Ralph Stanley (1927-2016), who started performing in the 1940s as half of the Stanley Brothers, and later as leader of his band The Clinch Mountain Boys. It's a modal tune accompanied by either major or minor chords and employs slides and lots of ringing open strings.

This set is part of my Bluegrass collection of tunes; for others, check out the Bluegrass Collection Index.