Chord Progression - Three-chord Progressions

Three-chord Progressions

Three-chord tunes, though, are more common, since a melody may then dwell on any note of the scale. Often the chords may be selected to fit a pre-conceived melody, but just as often it is the progression itself that gives rise to the melody.

The three-chord I - IV - V progression, a particularly popular kind of circle progression (see below), can be placed into a four-bar phrase in several ways that have been put to endless use in popular music. Ottman gives examples of favoured progressions:

• I - IV - V - V.
• I - I - IV - V.
• I - IV - I - V. (Common in Elizabethan music (Scholes 1977), this also underpins the American college song "Goodnight Ladies", is the exclusive progression used in Kwela.
• I - IV - V - IV.

Similar progressions abound in African popular music. They may be varied by the addition of sevenths (or other scale degrees) to any chord or by substitution of the relative minor of the IV chord to give, for example, I - ii - V. This sequence, using the chord based on the second scale degree, is also used cadentially in a common chord progression of jazz harmony, the so-called ii-V-I turnaround, on which are based the more ornate Coltrane changes.

Such progressions provide the entire harmonic foundation of much African and American popular music, and they occur sectionally in many pieces of classical music (such as the opening bars of Beethoven's Pastoral Symphony). Any of these progressions may be transposed into any key so that, for instance, the progression I - IV - V in the key of A will be played A - D - E, while in the key of C the chords will be C - F - G.

Where such a simple sequence does not represent the entire harmonic structure of a piece, it may readily be extended for greater variety. Frequently an opening phrase of the type I - IV - V - V, which ends on an unresolved dominant, may be "answered" by a similar version that resolves back onto the home chord, giving a structure of double the length:

I - IV - V - V

I - IV - V - I

Additionally, such a passage may be alternated with a different progression to give a simple binary or ternary form such as that of the popular thirty-two-bar form (see musical form).