Chord progression

A chord progression (also chord sequence and harmonic progression), as its name implies, is a series of chords played in an order. Part and parcel of this action is the idea that the chords relate to each other in some way, whether closely or distantly, and they as a whole become an entity in themselves. Chord progressions are central to most modern European-influenced music and create cyclic or sectional musical forms. Compare to a simultaneity succession.

A chord change is a movement from one chord to another and may be thought of as either the most basic chord progression or as a portion of longer chord progressions which involve more than two chords (see shift of level). Generally, successive chords in a chord progression share some notes. This provides harmonic continuity within the progression (see voice leading).

The most common chords in Western classical and pop music are based on the first, fourth, and fifth scale degrees (tonic, subdominant and dominant); see three chord song, eight bar blues, and twelve bar blues. The chord based on the second scale degree is used in the most common chord progression in Jazz, ii-V-I.

Chord progressions are usually associated with a scale and the notes of each chord are usually taken from that scale. Melodies and other parts usually comply with the chord changes in that their notes are usually taken from the chord currently playing. Notes which are not taken from the chord are called nonchord tones and usually resolve quickly to a chord tone.

In music of the common practice period generally only certain chord progressions are used and many of the progressions not used are not traditionally tonal.

Table of common progressions during the common practice period

Table of Common Progressions
I, i	May progress to any other triad. May interrupt any progression.
Major keys		Minor keys
ii	ii-V, ii-vii6°	ii6°	ii6°-V
		ii*	ii-V, ii-vii6°
iii	iii-ii6, iii-IV, iii-V, iii-vi	III	III-ii6°, III-iv, III-VI
IV	IV-I, IV-ii, VI-V, IV-vii6°	iv	iv-i, iv-ii6°, iv-V, iv-VII
		IV*	IV-V, IV-vii6°
V	V-I, V-vi	V	V-i, V-VI
		v*	v-VI
vi	vi-ii, vi-IV, vi-V, vi-iii-IV	VI	VI-ii6°, VI-iv, VI-V, VI-III-iv
vii6°	vii6°-I	vii6°/VII	vii6°-i/VII-III
* ii and IV in minor used with an ascending #6; v in minor used with a descending 7. See the article chord (music) and chord symbol for an explanation of the notation used in this table.

Rewrite rules

Steedman (1984) has proposed a set of recursive "rewrite rules" which generate all well-formed transformations of jazz, basic I-IV-I-V-I twelve bar blues chord sequences, and, slightly modified, non-twelve-bar blues I-IV-V sequences ("I Got Rhythm "). Important transformations include:

• replacement or substitution of a chord by its dominant or subdominant, example:

1 2  3 4   5  6   7    8    9  10 11 12
I/IV/I/I7//IV/VII7/III7/VI7//II7/V7/I/I//

• use of chromatic passing chords, example:

...7    8    9...
...III7/bIII7/II7...

• and chord alterations such as minor chords, diminished sevenths, etc.

Sequences by fourth, rather than fifth, include Jimi Hendrix's "Hey Joe":

1        2        3 4  5          6       7 8   9         10      11 12
bVi, bIII/bVII, IV/I/I//bVI, bIII/bVII, IV/I/I//bVI, bIII/bVII, IV/I/I//

These often result in Aeolian harmony and lack perfect cadences (V-I). Middleton (1990, p.198) suggests that both modal and fourth-orientated structures, rather than being "distortions or surface transformations of Schenker's favoured V-I kernel, it is more likely that both are branches of a deeper principle, that of tonic/not-tonic differentiation."

The chord sequence of The Beatles' "I Saw Her Standing There" derives from a tree with both subdominant and dominant branches.

Source

• Middleton, Richard (1990/2002). Studying Popular Music. Philadelphia: Open University Press. ISBN 0335152759.
  • Steedman (1984).

External links

• Olav Torvund's Chord progressions for Guitar website