Miss Libba learned to play by surreptitiously learning on her brothers guitar when he wasn't home. She couldn't restring it or he would have suspected something, so she developed her unorthodox style. Using her 1st finger on the bass gave it a certain feel which CANNOT be duplicated by us mere mortals. She wrote FREIGHT TRAIN when she was in her 'teens, I believe. When she got religion, she gave up playing guitar for many years, and only resumed playing after she went to work for the Seeger family. By the way, Jim Rooney who know is a big producer flatpicks bluegrass upside down & left handed.