The Indigo Foundation (Basic Blues)

2.7.1Introduction to Blues

The blues is a foundational pillar of popular music, influencing countless genres from jazz and rock and roll to soul, R&B, and hip-hop. Originating from African American communities in the Deep South of the United States around the late nineteenth century, the blues is both a musical form and a genre. It is rooted in African musical traditions, spirituals, work songs, and field hollers - an expressive synthesis born from the most difficult circumstances of American history and transformed into one of the most influential aesthetic traditions the world has ever produced.¹

Consider early recordings by pioneers like Robert Johnson ("Cross Road Blues," 1936) or Bessie Smith (St. Louis Blues, 1925), and later adaptations by The Rolling Stones or Eric Clapton. These musicians rely on the blues not just as a set of rules, but as a framework for emotional storytelling. The basic blues revolves around three core chords: the tonic (I), the subdominant (IV), and the dominant (V). However, unlike standard diatonic harmony where these chords might be major triads (as we explored in Chapter 2.4, Primary Chords), in the blues they are typically played as dominant seventh chords (I7, IV7, V7), creating a persistent, driving tension that defines the style.

To understand this, we must look at how these chords interact. In the key of C, the basic blues chords are C7, F7, and G7. This persistent use of dominant seventh chords challenges the traditional rules of functional harmony, as the tension does not always resolve in the expected classical manner. Instead, the tension itself becomes the resting state - an idea we will put on a firmer footing later in this chapter, and revisit when we look at extended harmony and advanced blues forms in Chapter 3.7 (Advanced Blues).

Exercise: Listen to Hound Dog by Big Mama Thornton (1952) or Elvis Presley (1956). Try to identify the three main chords (I, IV, V) as they cycle through the song. Notice how each chord feels like a dominant seventh.

2.7.2Blues Scales and Pitch Content

The melodic language of the blues is just as distinctive as its harmony. The pitch content of a blues progression can be extrapolated from the notes found in its core chords, but it is most commonly understood through the use of specific scales - the major and minor pentatonic scales, and the two blues scales they generate between them. Recall the fundamental scale structures we established in Chapter 1.4 (Scaling the Heights): both of the scales below build directly on those foundations.

A classic example of blues scale application can be heard in the guitar solos of B.B. King or the vocal improvisations of Bessie Smith. When improvising over a C blues, a musician might use the C major pentatonic scale (C, D, E, G, A) or the C minor pentatonic scale (C, E♭, F, G, B♭). Add the ♭5 to that minor pentatonic and you have the basic blues scale - C, E♭, F, G♭, G, B♭ - the six-note shape we built in Chapter 1.4, and the one most players mean when they say "the blues scale."

But the blues is rarely that tidy in practice. Players move between the major and minor pentatonics freely, sometimes inside a single phrase, and the ♭3 rubbing against the ♮3 is not a mistake to be resolved but the sound itself. Take both pentatonics together, add the ♭5, and you get the chromatic blues scale: C, D, E♭, E, F, G♭, G, A, B♭. Nine of the twelve pitches, with only the ♭2, the ♭6 and the leading tone left out - which is precisely what stops it collapsing into the chromatic scale and becoming no scale at all. It is a palette rather than a ladder, and it works over all three blues chords.

The most defining characteristic of the blues scale is the inclusion of blue notes - pitches that are performed at a slightly lower or inflected pitch than the corresponding note in the major scale for expressive purposes.² The most common blue note is the flattened third (e.g., E♭ in the key of C), which is often bent slightly sharp toward the natural third. Another crucial blue note is the flattened fifth (or sharp fourth, e.g., G♭/F♯ in C), which adds a distinctively dissonant, vocal quality to melodies.

Exercise: Play a C major triad on a piano or guitar. Now, play an E♭ along with it, and slowly bend the E♭ up toward E (if on guitar), or play them simultaneously. Observe the clash and the characteristic "bluesy" sound it creates.

2.7.3The 12-Bar Form and Variations

The structural backbone of most blues music is the 12-bar blues progression - a cyclical chord progression that unfolds over twelve measures, providing a reliable and predictable canvas for improvisation and storytelling. As we will see when we discuss song architecture in Chapter 4.8 (Advanced Form), the 12-bar blues is one of the most resilient modular structures in all of popular music.

Songs like Johnny B. Goode by Chuck Berry (1958) or "Pride and Joy" by Stevie Ray Vaughan (1983) are textbook examples of the 12-bar blues form. The standard structure consists of three four-bar phrases. The first four bars establish the main musical theme on the tonic chord (I). The next four bars repeat or develop this theme, moving to the subdominant (IV) before returning to the tonic (I). The final four bars provide a closing statement, moving to the dominant (V) for two bars and then resolving back to the tonic (I) for the last two. That is the Basic Blues in full: I7–I7–I7–I7 | IV7–IV7–I7–I7 | V7–V7–I7–I7. Every variation in the rest of this chapter is something added to that.

Players add to this basic form constantly, and a few of those additions are standard enough to have names. The two most common are the quick change, where the second measure moves briefly to the IV chord before returning to the I chord in measure three, and the quick return - sometimes called simply the IV in bar ten - where the tenth measure drops from V to IV so that the closing phrase comes home through the subdominant instead of straight off the dominant. Less common, and more strongly associated with jazz-inflected blues, is the quick transition, sometimes called simply the ♯iv diminished: the sixth measure becomes a ♯iv°7, the IV chord's root shoved up a half step into a diminished seventh, which then slides back down into the I. You will hear it all over Count Basie.

The 12-bar form itself encodes the blues feeling: the IV chord in bar 5 (the subdominant "turn") creates harmonic surprise and melodic opportunity. The V chord in bar 9 (the dominant) sets up the final resolution back to I. This harmonic architecture became the foundational grammar for all subsequent blues composition, jazz blues, and blues-inflected popular music.

The influence of this form extends far beyond traditional blues and rock. Sometimes the debt is structural outright, as in James Brown's funk masterpiece "I Got You (I Feel Good)" (1965), which is a twelve-bar blues from top to bottom. Sometimes it is looser but no less real: the Sugarhill Gang's Rapper's Delight (1979) is built over a replay of the disco-funk bassline from Chic's Good Times, itself heavily indebted to blues-based R&B.

Notice what the quick return does to the ending. The Basic Blues closes with the dominant resolving directly to the tonic - the Authentic Paradigm, plain and unmixed. Add the quick return, and that V–IV–I movement now blends both paradigms we studied in Chapter 2.4: the V chord still invokes the Authentic Paradigm, but the resolution passes through IV on its way home, giving the final arrival a distinctly plagal colouring. The two forces work together, just as we described there - and it is the variation, not the basic form, that puts them together. But do not mistake their presence for their authority. Both paradigms can be found operating in the blues; neither one rules it. This music follows a great many of tonality's habits without ever having agreed to its laws, and we will come back to that in a moment.

Exercise: Write out the Roman numerals for a standard 12-bar blues progression. Then, map those numerals to the chords in the key of A major (A7, D7, E7).

2.7.4V7 Chords in the Blues Context

In classical harmony, a dominant seventh (V7) chord serves a specific function: it creates tension that demands resolution to the tonic (I) chord. In the blues, the dominant seventh chord takes on a completely different role.

Consider the opening chord of Elvis Presley's Hound Dog (1956) or The Beatles' Day Tripper (1965). These songs begin on a dominant seventh chord (I7), but it functions as the "home" chord - not a chord demanding resolution. In the blues, the I, IV, and V chords are all typically dominant sevenths.

This means the pitch content of the chords includes minor sevenths (e.g., C7 contains B♭; F7 contains E♭). The presence of these minor sevenths over major triads is a hallmark of the blues sound. It creates a static tension - the chords sound "bluesy" rather than "unresolved."³

If the progression moves from V7 to IV7 to I7 in the final four bars - that is, if the quick return is in play - the resolution is stylistic rather than strictly functional in the classical sense. The IV7 chord in this context acts as a kind of softening buffer, blunting the edge of the dominant's drive home. And the tonic root is already sitting inside that IV7 - in C, the F7 contains the C itself - so the arrival is less a resolution to the tonic than a settling around a note that never left. A common tone does the work a leading tone would do elsewhere, and the landing is softer for it. This softer resolution is a key component of the blues sound, and it connects directly to the non-dominant harmonic grammar of the Mixolydian mode we explored in Chapter 2.6.

It is worth being precise about what kind of music we are describing. The blues borrows a great deal from common-practice tonality - the same three primary chords, the same pull toward a tonic worth returning to - but it does not obey the same rules, and judging it against them is a misdirection: it sends you looking for the wrong things and finding failures where there are none. Its home chord is a dominant seventh. Its central dissonances never resolve. The notes traditional theory would call wrong are the expressive point. The blues follows many aspects of traditional tonality while operating under its own set of principles, and this is the space in which the Dual Paradigms of Chapter 2.4 can be found at work - found at work, but not in charge. In a music where the dominant's urgency has been deliberately blunted, the plagal motion is not a weaker substitute for the authentic one; it is an equal partner, and often the more idiomatic of the two. Everett makes the same point taxonomically when he classifies blues-based rock as a coherent tonal system in its own right rather than a deviation from common practice.³

Exercise: Play a standard C–F–G progression using simple major triads. Then, play the same progression using C7, F7, and G7. Note how the addition of the minor seventh interval transforms the progression from a simple folk sound to a blues sound.

2.7.5Turnarounds

The end of a 12-bar blues progression rarely comes to a full stop. Instead, it employs a turnaround to propel the music smoothly back to the beginning of the next 12-bar cycle.

Listen to the final two measures of Robert Johnson's Sweet Home Chicago (1936) or Eric Clapton's Before You Accuse Me (1989). The turnaround is a musical figure, usually occupying bars 11 and 12, that sets up the return to the top of the form. Instead of resting entirely on the tonic (I) chord, the turnaround often moves to the dominant (V) chord in the very last measure, creating an expectation fulfilled when the next verse begins on the I chord.

Turnarounds can be simple chordal movements (like I–IV–I–V) or complex, descending chromatic lines played by a guitar or piano. They are a signature element of the blues style, serving simultaneously as a punctuation mark for the completed stanza and a springboard for the next. This concept of cyclical momentum is crucial - it is the same principle that drives the loop-based forms of modern pop and EDM that we discussed in Chapter 2.3 (Harmony).

Exercise: Listen to a blues song and focus entirely on the last two measures of each verse. Try to identify the moment the harmony shifts to the V chord to turn around back to the beginning.

2.7.6Blues Shuffles and Bass Patterns

While harmony and melody are crucial, the rhythmic feel of the blues is equally defining. The most iconic rhythmic feel in the blues is the shuffle. Recall our discussion of simple and compound meter in Chapter 1.6 (Measure and Meter) - the shuffle exists beautifully in the space between the two.⁴

Songs like Sweet Home Chicago or "Pride and Joy" are driven by a shuffle rhythm. A shuffle is based on a triplet subdivision of the beat, where the first note of the triplet is held longer than the second, creating a "long-short, long-short" galloping feel. This is often played on the ride cymbal or hi-hat by the drummer, and mirrored by the bass player and rhythm guitarist.

Accompanying the shuffle is often a specific bass pattern, such as the boogie-woogie bass line - an ostinato that outlines the chords of the progression, often using the root, third, fifth, and sixth of the chord (e.g., C–E–G–A over a C chord). This walking bass line provides a relentless, driving foundation that defines the groove of Chicago blues and early rock and roll.

One more device belongs here with rhythm rather than with harmony, because it alters no chords at all: stop time. The band plays a short figure at the top of the bar and then stops dead, leaving the singer alone in the hole it opens. The chords underneath are unchanged; what changes is the floor falling away beneath the voice.

The most famous instance is not, strictly speaking, a twelve-bar blues at all. Muddy Waters' "I'm Your Hoochie Coochie Man" (1954), written by Willie Dixon, runs on a sixteen-bar form: the first four bars are stretched to eight so the harmony sits on the tonic for the whole first half while the stop-time riff repeats, and only then does the song fall into the last eight bars of the familiar twelve-bar progression. Dixon said he expanded the form in response to amplification, which gave the instruments enough sustain to hold those longer spaces open.⁵ It is worth knowing that the definitive stop-time record is built on an expansion of the form rather than on the form itself.

Stop time works perfectly well in a plain twelve-bar, though, and when it does there is a small piece of craft worth listening for. At the end of the fourth bar, where the band would otherwise simply wait, players very often insert a walk-up - a non-standard but active transitional gesture - that carries the ear across the barline and into the IV chord in bar five. No two players do it the same way, and none of it is written down, but it is one of those unwritten habits that separates a form being executed from a form being played.

Exercise: Tap your foot to a steady 4/4 beat. Now, try to vocalize a shuffle rhythm over that beat ("dah-da dah-da dah-da dah-da"). Notice how it differs from a straight, even subdivision of eighth notes.