Big Walter Horton was so shy his peers nicknamed him Mumbles, yet when he raised a harmonica to his lips the sound was so bold that Willie Dixon called him the best he had ever heard. This episode traces how a kid from Horn Lake, Mississippi, born in 1921 and out of school by age seven, went from blowing into discarded tin cans on a porch to shaping the modern Chicago blues sound, largely from the shadows as a perpetual sideman.

We follow his verifiable 1939 debut backing Little Buddy Doyle in Memphis, the lost decade of the 1940s spent as a cook, undertaker, and ice hauler while he perfected his tongue-blocking technique and taught James Cotton and Little Walter, and his 1952 arrival in Chicago. The episode covers his short tenure in Muddy Waters’s band, the 1953 Sun Studio session with Sam Phillips that produced Easy, his celebrated 1956 solo on Jimmy Rogers’s Walking By Myself, and the disconnect between international tours and the poverty he returned to on Maxwell Street.

• How tongue blocking lets one harmonica player act as rhythm section and soloist at once, and why hauling ice may have built the lungs to power it
• Why a street-level instinctive player was fired from Muddy Waters’s tightly run band by the end of 1953
• What third position harmonica playing means and how his 1969 work with Johnny Shines showed an elite grasp of theory without reading a note
• The 1980 Blues Brothers shoot where he appeared on screen with John Lee Hooker but walked off rather than repeat takes, leaving his parts to be overdubbed
• The nystagmus behind the Shakey nickname, his death in Chicago on December 8, 1981, at age 60, his 1982 Blues Hall of Fame induction, and the 2008 Mississippi Blues Trail marker in Horn Lake