Once you have some idea of the association between chord symbols and scales, and how to develop a melodic line, you can start improvising over chord progressions. In performance situations, the rhythm section will be outlining the chord progressions in tempo, while you play improvised lines based on the associated scales. Often the chords will change every measure, and you must keep changing scales to keep up. However, you should not think one chord at a time. You should be trying to construct lines that lead from one chord to the next.
The third and seventh of each chord are the notes that most define the sound of the chord. If you emphasize these notes in your improvisation, it will help guarantee that your lines will accurately imply the changes. Conversely, if you emphasize the other scale tones, it can add a harmonic richness to the sounds. You are also free to use notes not in the scale at all. Bebop players often use a device called the enclosure, in which a target note is preceded by notes a half step above and below. This is related to the idea of a passing tone, except in the enclosure, the chromaticism is used to emphasize or delay a particular note rather than to connect two other notes. Other non-scale tones can be used as you see fit.
While there are many possible chord progressions, there are a few basic building blocks that account for many of the chord changes you will see. If you become familiar with these basics, you will be well on your way to being able to play over any set of changes that might come your way. Performers should practice the chord progressions described below in all twelve keys to gain the most fluency. You may wish to try out some specific patterns on these progressions, but more importantly, you should simply explore many different ideas on each progression in each key so you will be comfortable truly improvising on them, rather than just playing the licks with which you are comfortable in that key. You should experiment with different approaches and learn how to tailor your note choices for a given chord type in a given situation for the sound you are trying to achieve.
In addition to reading about these concepts you should try to listen specifically for these techniques being applied by other musicians. The most popular jazz musicians of the 1950’s make a good starting point. These include Miles Davis, Clifford Brown, Sonny Rollins, John Coltrane, Cannonball Adderly, Art Pepper, Red Garland, Hank Jones, Herb Ellis, Joe Pass, Paul Chambers, and Ray Brown. Any albums from that time period featuring one or more of these musicians are recommended for learning about playing changes.
The most important chord progression in jazz is the ii-V, which may or may not resolve to I. Most tunes will have ii-V progressions in several different keys sprinkled throughout. For example, consider the chord progression:
| Cmaj7 | Dm7 G7 | Em7 | A7 | Dm7 | G7 | Cmaj7 |.
There are three ii-V progressions here. Bar two forms a ii-V in the key of C, although there is no actual C (I) chord in bar three. Bars three through five form a ii-V-I in the key of D minor, and bars five through seven form a ii-V-I in C again. There are many devices that can be used when playing over ii-V progressions. Some of these are described below.
In a major key, the ii-V-I progression consists of a minor seventh chord, a dominant seventh chord, and a major seventh chord. The first scale choices you learned for these chords are dorian, mixolydian, and major. In the key of C, the chords are Dm7 – G7 – Cmaj7, and the associated scales would thus be D dorian, G mixolydian, and C major. As you may have noticed, these are all modes of the same C major scale. Thus when you see a ii-V progression in a major key, you can play the major scale of the I chord for the whole progression. This makes it somewhat easier to construct lines that lead from one chord to the next, or transcend the individual chords. This type of progression, where the scales associated with each of the chords are all modes of each other, is called a diatonic progression. While diatonic progressions are easy to play over, they can quickly become boring, since you are playing the same seven notes for an extended period of time. You can add a little variety by using one of the other scales associated with each chord, such as D minor, G dominant bebop, C lydian.
The most common way to add interest to a ii-V progression is to alter the dominant (V) chord. Often the alteration will already be specified for you, but even when it is not, you generally have the freedom to add alterations to dominant chords. It helps if the soloist and the accompanists are playing the same alterations, but this is not always practical when improvising unless your accompanist has incredible ears and can hear the alterations you are making, and in any case it is not actually all that important.
In the key of C, you might replace the G7 chord with a G7#11, a G7alt, a G7b9b5, or a G7+ chord, all of which still fulfill the dominant function in C but imply different scales. For instance, if you choose G7#11, the progression then becomes D dorian, G lydian dominant, C major.
Another possible alteration to the dominant is called the tritone substitution. This means replacing the dominant chord with a dominant seventh chord a tritone away. In the key of C, this would mean replacing the G7 with a Db7. This may seem a strange thing to do, but there are some very good reasons why it works. The third and seventh of a chord are the two most important notes in defining the sound and function of the chord. If you look at a Db7 chord, you will see it contains Db, F, Ab, and B, which are respectively the b5, 7, b9, and 3 of a G7 chord. The third and seventh of the G7 chord (B and F) become the seventh and third of the Db7 chord. Thus, Db7 is very similar to a G7b9b5 chord in sound and function. Furthermore, the melodic resolution of Db to C in the bass is very strong, functioning almost as a passing tone.
Once you have made the chord substitution, you can then play any scale associated with the Db7 chord, for instance yielding a progression of D dorian, Db mixolydian, C major. Using a scale other than mixolydian will yield some surprising things. Try a Db lydian dominant scale, which implies a Db7#11 chord for the substitute dominant. Does this look or sound familiar? It should, because the Db lydian dominant and G altered scales are both modes of the same Ab melodic minor scale. When you play lines based on Db lydian dominant, you are playing lines that are also compatible with G altered. Conversely, Db altered and G lydian dominant are both modes of the same D melodic minor scale, and can be used interchangeably. Furthermore, the Db and G HW diminished scales are identical, as are the respective whole tone scales. These are other reasons the tritone substitution works so well.
ii-V progressions in a minor key generally do not suffer the problem of sounding too diatonic. Since the harmonic minor is normally used to generate chord progressions in a minor key, a ii-V progression in A minor might consist of | Bm7b5 E7 | Am-maj7 |. If we try to build a ninth chord from the E7, we see the that the F natural in the key of A harmonic minor generates an E7b9 chord. Without any special alterations, this progression could imply B locrian, E HW diminished, and A melodic minor. These scales are sufficiently rich that further alterations are not necessary.
However, most of the same techniques from major keys can be used in a minor key as well. We can use the melodic or harmonic minor scales from the i chord, or the major bebop scale from its relative major, over the entire progression. We can use a different variation of the E7 chord such as E7alt or E7+, or even E7sus; we can make a tritone substitution to yield Bb7; and so on. We can also substitute for the ii chords, for example using the locrian #2 scale, or replacing the Bm7b5 with an ordinary Bm7 chord, where the F# comes from the key of A melodic rather than A harmonic minor. If we were to make a ninth chord, the C natural in the key of A melodic minor generates a Bm7b9 chord, which implies a B phrygian scale. We can even replace the ii Bm chord with a II B7 chord, especially a B7alt chord, which contains the D natural from the Bm chord. We can also alter the i chord, replacing it with a simple Am7 chord, and using any of the various possible scales associated with that chord such as A minor, A phrygian, A minor pentatonic, and so on.
The term “blues” is somewhat overloaded, describing a general style of music and a more specific category of chord progressions, as well as its colloquial meaning of a particular mood, as in the phrase “I’ve got the blues”. The blues as a style has a rich history that is beyond the scope of this primer. The basic twelve bar blues form was mentioned earlier. In its original form, still played often in rock and R&B music, only three chords are used: the I chord, the IV chord, and the V chord. The basic blues progression is:
|| I | I | I | I | which, || F | F | F | F |
| IV | IV | I | I | in the key of F, | Bb | Bb | F | F |
| V | IV | I | I || yields: | C | Bb | F | F ||.
The chords are usually all played as dominant seventh chords, although they are not actually functioning as dominant chords in that they do not resolve to a tonic. The F blues scale can be played over this entire progression. While the blues progression can be played in any key, the most popular keys among jazz musicians seem to be F, Bb, and Eb, whereas rock musicians often prefer E, A, D, or G. This has a lot to do with the way instruments are tuned. Popular jazz instruments such as the trumpet and the various members of the saxophone family are usually tuned in Bb or Eb, meaning that the notated “C” played on these instruments actually sounds like a Bb or Eb respectively. Music written for these instruments is therefore transposed. The fingerings for the instruments favors playing in the key of C, which is actually Bb or Eb, depending on the instrument. Guitars tend to dominate rock music, and guitars are tuned to favor the keys containing sharps.
Playing the blues scale over the basic three chord blues progression in a jazz setting gets old very quickly. Starting around the swing era, and most notably in the bebop era, musicians began to make additions to this simple formula. One common adaptation of the blues progression, which is still considered the standard for jazz jam sessions, is:
|| F7 | Bb7 | F7 | F7 |
| Bb7 | Bb7 | F7 | D7alt |
| Gm7 | C7 | F7 | C7 |.
This progression offers a wider range of scale possibilities than does the basic three chord blues. For example, bars 8 and 9 form a V-i in G minor, and bars 9-11 form a ii-V-I in F.
The idea of adding ii-V’s to the blues progression yields more variations. For example, consider:
|| F7 | Bb7 | F7 | Cm7 F7 |
| Bb7 | Bdim | F7 | Am7b5 D7alt |
| Gm7 | C7alt | F7 D7alt | Gm7 C7alt |.
This particular progression is especially common in bebop and later styles. Note the substitution of a Bb ii-V-I in bars 4-5, a G minor ii-V-i in bars 8-9, and a G minor V-i in bars 11-12. Also note the diminished chord in bar
6. This diminished chord is serving as a substitute for the dominant seventh, since both Bdim and Bb7b9 share the same Bb HW (B WH) diminished scale. This same substitution can be made for the second half of bar 2.
Other variations can be made using tritone substitutions. For example, Ab7 can be played instead of D7alt in the second half of bar 8. You can also change the qualities of the chords, for instance replacing that Ab7 with an Abm7. Another common substitution is A7alt for the F7 in bar 11. This substitution works because the chords share several notes, including the tonic, F, and because the A7alt forms part of a G minor II-V-i progression with the D7alt and Gm7 that follow.
Charlie Parker carried these types of substitutions to an extreme in “Blues For Alice”. The chord progression in that tune is:
|| Fmaj7 | Em7b5 A7b9 | Dm7 G7 | Cm7 F7 |
| Bb7 | Bbm7 Eb7 | Am7 D7 | Abm7 Db7 |
| Gm7 | C7 | Fmaj7 D7alt | Gm7 C7 |.
This uses most of the techniques described above. You may wish to play with this progression for a while.
The George Gershwin song “I Got Rhythm” is the source for one of the most popular chord progressions of the bebop era, second only to the blues progression. This form is often called simply rhythm changes. As with the blues progression, there are many possible variations on rhythm changes. Most tunes based on rhythm changes are played in the key of Bb, and are played at very fast tempos, often well over 200 beats per minute. These songs have a 32 bar AABA form based on the chord progression:
A || Bbmaj7 G7 | Cm7 F7 | Bbmaj7 G7 | Cm7 F7 |
| Fm7 Bb7 | Ebmaj7 Ab7 | Dm7 G7 | Cm7 F7 ||
A || Bbmaj7 G7 | Cm7 F7 | Bbmaj7 G7 | Cm7 F7 |
| Fm7 Bb7 | Ebmaj7 Ab7 | Cm7 F7 | Bbmaj7 ||
B || Am7 | D7 | Dm7 | G7 |
| Gm7 | C7 | Cm7 | F7 ||
A || Bbmaj7 G7 | Cm7 F7 | Bbmaj7 G7 | Cm7 F7 |
| Fm7 Bb7 | Ebmaj7 Ab7 | Cm7 F7 | Bbmaj7 ||
This progression contains many ii-V progressions. Any of the standard alterations described under ii-V progressions above can be used when playing rhythm changes. Many tunes contain slight alterations to this basic progression, especially in the last four measures of the A sections. Some of the common alterations are to replace the second chord G7 with a diminished chord Bdim, or to replace the fifth chord Bbmaj7 with Dm7. The former substitution has already been described under the diminished scale. The latter replaces a I chord with a iii chord, which has three of four notes in common, and the respective scales differ by only one note. Furthermore, the Dm7 and following G7 form a ii-V in C minor, so this is an especially strong substitution harmonically.
The important characteristics of rhythm changes are the repeated I-VI-ii-V (or substitutes) in the first four bars of the A sections, and the basic tonality movements by fifths in the bridge, leading back to the original tonic in the last A section. If you intend to become an improvising musician, you should become fluent in the basic rhythm changes, particularly in the key of Bb, and become familiar with the particular variations associated with specific tunes. This is also a good opportunity to try out what you have learned about ii-V’s, and to work on you up tempo playing.
John Coltrane, through original compositions such as “Giant Steps” and “Countdown” on the album Giant Steps, and arrangements of standards such as “But Not For Me” on the album My Favorite Things, became known for using a particularly complex progression that is often called the Coltrane changes, although he was not the first or only musician to make use of it.
The primary characteristic of Coltrane changes is tonality movement by major thirds. The progression to “Giant Steps” is:
|| Bmaj7 D7 | Gmaj7 Bb7 | Ebmaj7 | Am7 D7 |
| Gmaj7 Bb7 | Ebmaj7 F#7 | Bmaj7 | Fm7 Bb7 |
| Ebmaj7 | Am7 D7 | Gmaj7 | C#m7 F#7 |
| Bmaj7 | Fm7 Bb7 | Ebmaj7 | C#m7 F#7 ||
The first key center here is B, then G, then Eb, and it continues to cycle through these three keys, which are a major third apart.
Coltrane was able to develop this idea in many ways. For example, he used it as a substitute for an ordinary ii-V progression. The progression to “Countdown” is loosely based on that to the Miles Davis composition “Tune-up”. The latter tune begins with the four measure progression:
| Em7 | A7 | Dmaj7 | Dmaj7 |,
which is a vanilla ii-V-I progression in D major. The first four bars of “Countdown” are:
| Em7 F7 | Bbmaj7 Db7 | Gbmaj7 A7 | Dmaj7 |.
Coltrane starts with the same ii chord, and then modulates to the dominant seventh chord one half step higher. From there, he launches into the cycle of major thirds, going from the key of Bb to Gb and finally back to D. The next four bars of the tune are identical harmonically, except they are based on a ii-V in the key of C; the next four bars are the same in the key of Bb.
Soloing over Coltrane changes can be challenging, since the apparent key center changes so often. You cannot simply play a single diatonic scale across several measures. The tunes are usually played at fast tempos, and it is also easy to fall into the trap of playing nothing but arpeggios outlining the chords. You must try to be especially conscious of playing melodically when soloing over a progression as complex as the Coltrane changes.