BASIC CHORDS JAZZ

BASIC CHORDS

The most basic chord formation is a triad, consisting of the root, 3rd and 5th.

ex 1a: C major (triad)
Jazz rarely uses triads: chords usually have at least four notes so the diatonic 7th is added (ex 1b). Added notes beyond the 7th are called upper extensions
We shall be looking at chord types in two ways:

1. As chords functioning diatonically within a key
2. As different types of chords based on one root, which can function in various keys

A) Chords functioning diatonically within a major key:

ex 1b: Diatonic chords of C major

N.B. A 6th is an alternative to the major 7th on chords I and IV. This usually occurs when either:
a) the 6th is the melody note,
or
b) when the root is the melody note (to avoid a semitone interval between melody note and 7th. Note: this semitone interval is fine when it is between inside parts of an inversion of a chord)

As you can see diatonic four-note chords in a major key fall into four different categories:

Chord	Symbol	Defining Intervals
chords I and IV	major 7	contains major 3rd and major 7th
chord V	(dominant) 7	contains major 3rd and minor 7th
chords II, III and VI	minor 7	contains minor 3rd and minor 7th
chord VII	half diminished (minor 7 b5)	contains minor 3rd, a diminished flattened) 5th and minor 7th

It is important to learn all diatonic chords in all keys. Using the roman numeral system helps; e.g. chords II, III and VI in any major key are always minor 7 chords.

Roman Numeral (RN) analysis:

This is a common way of analyzing the harmony of a tune. Instead of quoting the actual chord symbols (Dm7 - G7 -Cmaj7), it can be useful to use the roman numerals along with the type and extension of the chord. (IIm7 - V7 - Imaj7). This helps to memorise short chord progressions in any key. I would advise against using lower case for minor 7 (e.g. ii7 - V7 - I) as this can be misleading. This can become more complex as many jazz tunes consist of short temporary modulations, known as key centres. This will be discussed later.

B) Different types of chords based on one root:

ex 1c: basic chords:

Chord type	Possible functions in different keys
Major 7	I of C, IV of G
Dominant 7	V of F
Minor 7	II of Bb, III of Ab, VI of Eb
Half diminished (minor 7 flat 5)	VII of Db

There are two further basic chord types that are not diatonic in a major key but are also very important:

1. The diminished 7 chord (ex 1c-2). It is not always necessary to write the 7 in the chord symbol, it is assumed that all diminished chords are four note chords rather than triads.
2. The augmented chord. (ex 1c-3) . In jazz this is nearly always a dominant 7 chord with an augmented 5th so it is best to refer to it as a 7 augmented (As in C7 augmented).

Note that 7 on its own always means a dominant 7 type chord, a major 7 isalways denoted major or one of its abbreviations.
The table in ex 1d shows some alternative spellings for chord symbols. Only symbols in red font are recommended for clarity (A more comprehensive table can be found on the jazz chord symbol chart)

C major 7	Cmaj7	Cma7	CΔ	CM7
C7	C7
C minor 7	Cm7	Cmin7	C-7	C-
C half diminished (minor 7 b5)	Cø7	Cm7 b5	Cmin7 b5	C-7 b5
C diminished 7	Co (7)	C dim (7)
C7 augmented	C7+	C7aug	C7+5	C+7

ex 1d: alternative spelling of chord symbols.
With the exception of tritone substitutes and diminished scales and arpeggios, correct enharmonic spelling is necessary, e.g. the 7th degree of a B major scale is A# not Bb, the 3rd of Eb minor is Gb not F#.

CHORD PROGRESSIONS

Apart from blues and early jazz progressions, the traditional I-IV-V sequence is not common in jazz. One of the most basic chord progressions is I-VI-II-V (ex 2a).

ex 2a (Ima7-VIm7-IIm7-V7)
As in classical harmony there are 3 main areas: tonic, subdominant and dominant. It can be useful to think of tonic as home, subdominant as away from home and dominant as returning home.
1) Tonic area The tonic area obviously includes chord I, but also includes chord III and sometimes chord VI. The chords are similar because their roots are a diatonic third away from chord I (three out of the four notes of these chords are the same as those in chord I). Diatonic root movement of a 3rd is therefore seen as a weak progression. Chord III is often used as a substitute for chord I.
2) Subdominant area Traditionally this is chord IV but also includes chord II and sometimes chord VI. Chord VI is a diatonic 3rd away from chord I and chord IV hence it can be seen either as tonic or subdominant, depending on context. In jazz the II chord is more common than the IV chord as a subdominant, but it also functions very commonly as a lead in to the dominant V chord. IV is very common as a subdominant in blues.
3) Dominant area Chord V and chord VII. The dominant quality of a chord is usually defined by the tritone (flattened 5th) interval which creates what is traditionally thought of as a dissonance or a need to resolve to a chord that sounds more at rest (ex 2b). The VII is rarely used as a dominant.

ex 2b: Resolution of tritone.

SECONDARY DOMINANTS

Conventionally a secondary dominant is a V7 of V7 chord: in the key of C, instead of preceding G7 by Dm7, the G7 is preceded by D7 - the dominant chord in the key of G. An actual modulation does not occur because the G is not a tonic, it is a G7 and therefore functioning in the key of C (ex 2c). In this case it is created by chromatically altering the 3rd of the Dm7 chord from minor to major.

ex 2c: Secondary dominant: chord II7 (V7 of V)
In practice any chord that is not a tonic chord can be preceded by a secondary dominant.
When analysing this progression we call it II7-V7-I. From this it is obvious that the II chord is a dominant 7th rather than a minor 7th, which would have been called IIm7.
If we look again at a I-VI-II-V sequence we could instead create a secondary dominant of the IIm7 by chromatically altering the VIm7 to VI7. It is extremely common to alter the VI chord in this way: one advantage of changing m7 chords to secondary dominants is that there are more interesting sounding extensions and alterations available on dominant 7th chords.

ex 2d: Secondary dominant of II
It is also very common in jazz to use chord III as a substitute for chord I (see Tonic Area)

ex 2e: Substitution of chord III for chord I
Although they never actually resolve, the Em7 and A7 could be also viewed as IIm7 V7 in the key of D. In this case the 3^rd scale degree of the tonic is not present in either chord so the key centre could actually be either D major or D minor. For now we shall consider thisalternative key centre to be D major.
Looking at it like this, there are two ways to describe the progression in ex 2e using RN analysis:
(a) C: IIIm7-VI7-IIm7-V7-Ima7 etc.
(b) D: IIm7-V7 C: IIm7-V7-Ima7 etc.
Method (a) defines all the chords in their relationship to the key of the tune.
Method (b) defines the chords in their relationship to the key centres (D and C) for each II-V progression.
Although theoretically method (a) is the correct analysis - A7 is a secondary dominant: it precedes Dm7 which is functioning in the key of C so the progression does not actually modulate -in practice method (b) can often be more useful to the improviser (See Modes)
A secondary dominant can have its own secondary dominant. We could take a diatonic IIIm7-VI7-IIm7-V7 sequence and make all the minor 7 chords secondary dominants.

ex 2f: (1) Diatonic III-VI-II-V sequence
(2) Minor 7 chords replaced by secondary dominants*
N.B. These chords are voiced to allow the top and inside parts to move smoothly. (Compare the root position voicing in ex. 2c, d and e). This type of voicing is typical of horn parts or right hand piano voicing. A bass part or left hand would normally supply the roots.