WINSTON-SALEM, N.C. — Doc Watson, the Grammy-award winning folk musician whose lightning-fast style of flatpicking influenced guitarists around the world for more than a half-century, died Tuesday at a hospital in Winston-Salem, according to a hospital spokeswoman and his manager. He was 89. Watson, who was blind from age 1, recently had abdominal surgery that resulted in his hospitalization. Arthel "Doc" Watson's mastery of flatpicking helped make the case for the guitar as a lead instrument in the 1950s and 1960s, when it was often considered a backup for the mandolin, fiddle or banjo. His fast playing could intimidate other...