Function And Resolution

This is a preview of the educational program A Jazz Improvisation Almanac which is under development for the Outside Shore Music Online School. Feel free to browse this preview and learn what you can from it. For a more completed product, though, check out the original freely browsable jazz textbook, A Jazz Improvisation Primer.

The various diatonic chords tend to fill specific roles in Western harmony, both when considered alone and when considering the relationship between successive chords in a progression. This section describes some of those roles.

The chord built on the root of a scale is called the tonic. The tonic is the chord on which a progression feels as if it is complete, although it may occur at points other than the end as well. For instance, here is a progression in the key of Bb:

[EXAMPLE]

In major keys, the tonic or I chord is major. In classical harmony, the tonic is almost always a simple triad as in the previous example, but in jazz, the major seventh is often used:

[EXAMPLE]

In general, classical musicians are careful to distinguish between triads and seventh chords, whereas jazz musicians are apt to consider any chord to suggest a seventh chord, or indeed, an entire scale, as will be seen in the chapter on melody. Thus, when you see a I used to denote a scale, it can usually assumed to be a major seventh chord rather than a triad.

In minor keys, the i chord is a minor chord, but similarly serves the tonic function:

[EXAMPLE]

The i chord is almost always played as a triad in classical music. In jazz, the minor seventh from the natural minor may be used:

[EXAMPLE]

Or the minor-major seventh from the harmonic or melodic minor scales may be used:

[EXAMPLE]

This m-maj7 chord is sometimes called the tonic minor chord to distinguish it from the ordinary minor seventh chord, which is also found as the ii chord in a major scale:

[EXAMPLE]

However, some musicians use the term tonic minor to describe a minor chord of any type that happens to be the tonic chord of the key.

After the tonic, the next most important chord in establishing a sense of tonality is the dominant chord, built on the fifth degree of the scale. This chord strongly tends to resolve to the tonic:

[EXAMPLE]

In minor keys, the harmonic or melodic forms are generally used so that the dominant chord is major:

[EXAMPLE]

In both major and minor keys, when resolving to the tonic, a dominant seventh chord is often used for the V, regardless of whether or not this is explicitly specified:

[EXAMPLE]

When analyzing a chord progression, the last few chords are referred to as a cadence. The V-I cadence, or V-i in a minor key, is by far the most common and powerful and is called an authentic cadence:

[EXAMPLE]

The chord built on the fourth degree of the scale is called the subdominant. In a major key, the IV chord, is, like the I chord, a major seventh, and therefore can also serve as a place of rest in a progression. This rest is usually only temporary, however, as the piece eventually returns to the tonic. Consider for example the following progression:

[EXAMPLE]

The IV chord sometimes occurs in cadences and resolves directly to the tonic. This resolution downward by fourth is called a plagal cadence, and is most familiar as the "Amen" at the end of hymns:

[EXAMPLE]

In minor keys, the subdominant may be either minor, as in the natural and harmonic minor scales:

[EXAMPLE]

Or it may be major, as in the melodic minor:

[EXAMPLE]

The I, V, and IV or iv chords are considered the primary triads in classical theory, and it is possible to harmonize all the notes of the major or minor scale using only these chords:

[EXAMPLE]

The remaining diatonic triads are called the secondary triads in classical theory. The words "tonic", "dominant", and "subdominant" when applied to the primary triads refer to the function or role of these chords in a chord progression. When classical musicians speak of functional harmony, they mean an analysis of the chords within a progression to determine their function. Any chord other than a primary triad used in a progression can usually be related to one of these three functions in some way.

One of the ways to relate a secondary triad to one of the primary functions is through the concept of substitution. Chords with two notes in common often sound very similar, even though they may be built on different roots and one may be minor while the other is major.

For example, in the harmonization of the major scale using primary triads, note the last three chords form a IV-V-I cadence:

[EXAMPLE]

Since the IV and ii chords share two notes, they may substitute for each other. If the ii chord is used instead of the IV chord in the above cadence, the result is a ii-V-I cadence:

[EXAMPLE]

This particular progression is extremely important in jazz, and is indeed considered more fundamental than IV-V-I. Entire books have been written on the ii-V-I chord progression and how to improvise over it. The ii, V, and I chords are the building blocks of jazz harmony. In a major key, these are minor, dominant, and major chords respectively. In a minor key, the ii chord may be a half-diminished chord:

[EXAMPLE]

These four categories of chords - major, minor, dominant, and half-diminished - are thus considered the fundamental chord types in jazz.

In a ii-V-I progression, note that the interval between the roots of the ii and V chords is a perfect fourth upwards, as is the interval between the roots of the V and I chords. In general, it is common to have root movement upward by fourth, regardless of the degrees of the roots with respect to the original key. For example, in the key of C, the following progression uses this root movement at all points except between the second chord (F) and the third (Em):

[EXAMPLE]

Dominant seventh chords and minor seventh chords both tend to resolve up a fourth. Major seventh chords have no particular resolution tendencies.

Besides the ii chord, the other secondary triads can be used to substitute for primary chords as well. The iii and vi chords each share two notes with the I chord and therefore are often used as substitutes for the tonic. The particular cadence V-vi is especially common in classical music and is called a deceptive cadence, since the vi comes as a surprise to the ear expecting a I chord:

[EXAMPLE]

In minor keys, the VI is major, while the i is minor. The V-VI cadence sounds like this:

[EXAMPLE]

In a major key, if the iii chord is used as a substitute for the tonic in an authentic cadence, note that the iii chord shares two notes with the V chord preceding it as well as the I chord for which it is substituting:

[EXAMPLE]

This particular resolution is commonly used in jazz as part of what is called a turnaround, as will be seen later.

Whenever the root moves by a third in a major key, there will be two tones in common between the chords. This includes resolution in either direction between I and iii, ii and IV, iii and V, IV and vi, and vi and I in a major key:

[EXAMPLE]

These resolutions sound particularly smooth because so many notes are held in common. On the other hand, when roots move by step, there are no common notes, and the harmonic motion is more strongly emphasized:

[EXAMPLE]

In minor keys, chords a third apart may differ by more than one note if they come from different varieties of the minor scale. For instance, if the ii chord is used from the melodic minor, and the iv chord is taken from the natural minor, then they have only one note in common:

[EXAMPLE]

In general, chord progressions in minor keys tend to use chords from all three forms of the minor scale.

So far, we have concentrated on the major and minor triads. The diminished triads tend to be used much less often.

The diminished chord built on the seventh degree of the major scale is contained within the V7 chord:

[EXAMPLE]

It can therefore substitute for that chord, as in the following viio-I progression:

[EXAMPLE]

Similarly, the iio chord in the natural minor is contained within the VII7 chord and can therefore substitute for that chord, as in the following iio-III progression:

[EXAMPLE]

Root movement by step, third, and fourth cover all possible resolutions, if one considers movement in both directions. For example, movement by sixth is the same as movement by third in the opposite direction:

[EXAMPLE]

Thus, we have covered all the diatonic chords and their various relationships. Jazz musicians playing tonal music should be familiar with this material as it can help suggest patterns for use in improvisation.

Copyright 2000 Outside Shore Music
Authored by Marc Sabatella

Function And Resolution