
W. C. Handy is often called "the father of the blues." Though he didn't invent the form, he was inspired by hearing Delta blues musicians to write and publish the first 12-bar blues tune ("Memphis Blues," in 1912) that crossed over and became a pop hit. Two years later he wrote (or re-wrote, from a folk blues he had heard) "St. Louis Blues," which would become one of the most recorded and performed blues tunes of all time. It has three sections, one of which is a 16 bar structure, often played in tango rhythm. This is the middle section, bookended by two 12-bar strains that came to define the 12-bar format. Many would call Bessie Smith's 1925 recording, which includes Louis Armstrong on cornet, the definitive version of the tune. This key-of-D arrangement features a repetitive, monotone thumb/bass backup: the thumb plunks out the root bass note of each chord, four beats to the bar, while the fingers pick melody, during the solo, and provide fills and articulate chord changes during the accompaniment to the vocal. All three sections of the tune are played in the first 5 frets, but the many "extra" chord changes are a lesson in how to ornament and vary a standard 12-bar blues progression.