The twelve-bar blues form became the most common current structure of blues music in the first decades of the 20th century.
 Two of the first published blues songs, "Dallas Blues" (1912) and "Saint Louis Blues" (1914), were 12-bar blues with the AAB lyric structure
"=== Minor blues ===There are also minor twelve-bar blues, such as John Coltrane's "Equinox" and "Mr

