Chapter 5: The Blues
Because the blues is the basis of most American music in the 20th century. It's a 12-bar form that's played by jazz, bluegrass and country musicians. It has a rhythmic vocabulary that's been used by rock n' roll. It's related to spirituals, and even the American fiddle tradition."
—Wynton Marsalis
The 12-bar blues is one of the most recognizable and influential forms in American music. Structurally, it is built around three lines of lyrics, typically in an AAB format, with each line corresponding to four bars of music, totaling twelve bars. The first line is repeated, creating a sense of emphasis and expectation, and the third line typically offers a twist or commentary. Lyrically, blues songs often deal with themes of personal hardship, love, loss, and resilience. Lyrics can be narrative or introspective and often employ clever wordplay, innuendo, and double entendre. Common subjects include sexual relationships, heartbreak, financial struggle, and social inequality. Despite the heaviness of these topics, blues lyrics are frequently witty, poetic, and humorous.
Harmonically, the 12-bar blues follows a repeating chord progression based on the I, IV, and V chords of a given key:
A: I - I - I - I
A: IV - IV - I - I
B: V - IV - I - I
This simple yet powerful progression allows for endless variation and improvisation, forming the backbone of countless blues, jazz, and rock songs.
Another defining musical feature of the blues is the use of blue notes. These are notes that are deliberately bent, smeared, or played slightly flat relative to standard pitch. They give the blues its expressive tone and emotional depth. . Vocalists may achieve this naturally through phrasing and inflection, while instrumentalists, especially guitarists, use techniques such as string bending or slide guitar (also called the bottleneck technique) to produce the same effect. Blue notes are closely tied to the blues scale, a variation of the pentatonic scale. The pentatonic scale, commonly found in folk traditions around the world, is a five-note scale that omits certain tones from the more familiar seven-note major or minor scales, creating a more open and flexible melodic framework. The blues scale modifies the minor pentatonic scale by adding an extra note, the so-called "blue note," usually a lowered fifth, also called a flat five or diminished fifth. This scale creates a sense of tension and release, giving blues melodies their distinct sound and emotional intensity.
To express blue notes, guitarists frequently use a technique called string bending, in which the player pushes or pulls the string across the fretboard to raise the pitch slightly. This allows for fluid, vocal-like inflections that blur the line between one pitch and the next. Another signature blues technique is the use of a slide or bottleneck, a smooth object such as a metal or glass tube, worn on a finger and slid along the strings. This technique allows the player to glide between notes with a moaning or wailing quality. Originally, blues musicians often used the neck of a glass bottle, which is where the term bottleneck slide comes from, to create this effect.
Together, the 12-bar form, distinctive lyrical structure, and use of blue notes make the blues a deeply expressive and flexible musical style. Another core element of blues performance is call and response, a technique deeply rooted in African musical traditions and central to nearly every form of African American music, whether sacred, secular, or popular. A central feature that united these forms, and one that would carry over into the blues and beyond, was call and response.
Before the blues emerged as a distinct genre, African American communities had long relied on music, particularly spirituals, field hollers, and work songs, not only for emotional expression but also for survival, communication, and resistance. These early musical forms developed during slavery and Reconstruction, shaped by the harsh realities of forced labor, racial oppression, and religious hope.
Spirituals, rooted in Christian faith and biblical themes, allowed enslaved people to express sorrow, endurance, and longing for freedom. Many spirituals also contained coded language that communicated escape plans or subversive ideas under the watchful eyes of slaveholders. Work songs, on the other hand, were rhythmically structured to match the labor at hand, whether chopping wood, hoeing fields, or laying railroad tracks. These songs helped coordinate group tasks, maintain a steady pace, and lift morale during grueling physical work. Importantly, both spirituals and work songs were often improvised, passed down orally, and meant to be performed communally.
This musical structure creates a back-and-forth exchange, like a conversation in sound. A solo voice or instrument presents a phrase (the “call”), and another voice or group answers (the “response”). In spirituals, this might occur between a church leader and the congregation; in work songs, between a lead singer and fellow laborers; and in blues, between a vocalist and their guitar or piano. It creates interaction and emotional dialogue within a performance. A clear example of call and response can be heard in Louis Armstrong’s “West End Blues,” where, during the third chorus, Armstrong sings a phrase that is immediately echoed and answered by the clarinetist (1:24). This conversational quality gives the performance a sense of depth and spontaneity, underscoring the roots of blues in oral and communal traditions. Call and response helped establish rhythm and cohesion in communal settings, but it also modeled a deeper cultural value: dialogue. It emphasized participation, interaction, and responsiveness, principles that would continue to define African American musical forms from blues and jazz to gospel, soul, funk, and hip-hop. In the blues, this dynamic interaction allowed musicians to mirror the emotional highs and lows of their lyrics through instrumental echo, improvisation, or contrast, creating performances that felt personal, spontaneous, and deeply human.