Pentatonic (five-note) scales are the basis for simple folk melodies and nursery rhymes all around the world. So how is it that they can be used in jazz so powerfully, to create so many colors and degrees of tension and dissonance? Let’s take a look.
We’re all familiar with the notes in a C major pentatonic scale: C, D, E, G, A.
Look at the five notes arranged on the circle of fifths:
I’ve circled C in bold to indicate that it is the root of the scale. Notice that the other notes of the scale lie clockwise from C, which indicates that they are bright sounding notes relative to C. (See my post about brightness & darkness.) Hence the majorness of the scale.
The minor pentatonic scale is simply the fifth mode of the major pentatonic scale. That is to say, when you start a major pentatonic scale on its fifth note, the result is a minor pentatonic scale:
The minorness of this mode stems from the fact that now most of the notes lie counterclockwise from A, the new root, which makes them sound dark relative to A.
For an apples-to-apples comparison, look at the C minor pentatonic scale next to the C major pentatonic, pictured below. You can see that the three brightest notes of the C major pentatonic (D, A, E) have been replaced by notes that are dark relative to C (F, B, E). That results in the minor quality:
For expedience, I’ll use “C pentatonic” to mean C major pentatonic; if I mean a minor pentatonic scale I’ll say so explicitly.
Standard Pentatonic Scales
Among the pentatonic scales of western harmony, the major and minor pentatonic scales are by far the most widely used. For convenience, let’s refer to major pentatonic scales and their modes—including the minor pentatonic—as standard pentatonic scales. As collections of notes, standard pentatonic scales are all identical; they differ only with regard to transposition and which of their five notes we consider the root.
Standard pentatonic scales have as much tonal focus as possible.
Looking at the diagrams above, you can see that the notes lie clustered together as tightly as possible on the circle of fifths. Since notes near each other on the circle are tonally similar, that’s a visual way of understanding that the scale has as much tonal focus as possible. This tonal focus is something you can hear in the standard pentatonic scales and not in seven-note scales. The similarity of the notes leads to a coherence of the sound.
Standard pentatonic scales have as little dissonance as possible.
The more half-steps and tritones are contained in a scale, the greater the scale’s potential for dissonance.
All major scales (and all their modes) contain two half steps and one tritone:
Melodic minor scales (and their modes) contain an additional tritone:
A whole tone scale contains no half steps but three tritones:
And any diminished scale contains four half steps and four tritones:
But a standard pentatonic scale contains neither half-steps nor tritones. In fact, of all the collections of notes that contain neither half-steps nor tritones, the largest ones are all standard pentatonic scales; all others have fewer than five notes.
Because standard pentatonic scales are so tonally focussed, their notes are somewhat interchangeable. Substituting one note for another in a pentatonic line will change the shape of the line, but it does not much change the overall harmony implied by the line. By contrast, seven note scales contain notes that are very harmonically distant such as half-steps and tritones. These create mini-cadences of tension and release within the line which, if they’re not timed sensibly, can sound like nonsense.
To see what I mean, listen to two lines which I generated randomly by computer—one using the major pentatonic scale, and one using the major seven-note scale. To provide context, I’ve added a simple accompaniment to the tracks—please excuse the corny computer output.
Notice that the random heptatonic major line sounds awful, whereas the pentatonic line sounds quite passable. Even random note selection can’t make a line that uses the major pentatonic scale sound bad.
You might object that the major heptatonic scale contains F, an “avoid note,” whereas the major pentatonic scale does not… and that gives the pentatonic scale an unfair advantage. To level the playing field, let’s listen to the Lydian scale, which contains no “avoid note.” Here we compare a random C Lydian line to a random line using C Lydian’s pentatonic counterpart (explained below), the G Pentatonic scale:
Once again, the random pentatonic line easily beats the random heptatonic line.
The Specialness of The Major & Minor Pentatonic Scales
One interesting point before we move on. If we look at the major pentatonic scale on the circle of fifths, we can observe that the major pentatonic scale of a key is the only standard pentatonic scale that contains that key’s major triad. That’s because the root and the major third form (of course) a major third interval, which spans four perfect fifths—or, five spots on the circle of fifths. The root is the darkest and the major third is the brightest and all the others must fall in between. Likewise, the minor pentatonic scale is the only standard pentatonic scale that contains a key’s minor triad—because the minor third and fifth form a major third interval which, too, determines the brightest and darkest notes of the pentatonic scale. We can summarize:
The major pentatonic scale is the only set of five contiguous notes on the circle of fifths that contains the major triad.
The minor pentatonic scale is the only set of five contiguous notes on the circle of fifths that contains the minor triad.
How to use pentatonic scales
Soo… how do we actually use pentatonic scales when we improvise?
Once you choose a pentatonic scale, improvising using that scale is conceptually easy. Because even random note choice gives reasonable results, a player can use simple systems to create myriad pentatonic patterns that sound good. There’s no shortage of books & blogs full of such systems and patterns—for instance, Volume Two of Jerry Bergonzi’s Inside Improvisation Series. So let’s take on the key question of which pentatonic scales to use over which chords.
Pentatonics over Major Chords: Wratcheting up Brightness
You’d think that if the major pentatonic scale were good for one thing, it would be for playing over major chords. Indeed, a C major pentatonic scale can be used over a C major chord. But the story is more complex. Here is a C major scale:
Note that there are three major pentatonic scales contained in the seven notes of a C major scale. In addition to the C pentatonic there are the F and G pentatonics:
In the F pentatonic scale, E, which is the brightest note of the C pentatonic, is replaced by the darker F. The F pentatonic is a poor choice to use for C major; it is so dark, relative to C, that it does not contain the most characteristic note of a major chord: the major third. Instead it contains the F natural, a tension note in C major that wants to resolve to the E that is absent from the scale.
By contrast, the brighter G pentatonic (in which the C, the darkest note of the C pentatonic, is replaced by the brighter B) is a fine choice for C major improvisation. Yes, in order to contain the five brightest notes of the C major scale, one of the notes it omits is C, the root itself. But nothing says that we have to play the root of a chord when we improvise. I’ve indicated that C is still the root of the chord by enclosing it in a bold circle, but that it is not in the scale by making that circle dashed.
Listen again to an example of the G pentatonic scale used over C. Here is our same random pentatonic line transposed from C to G, over the C accompaniment:
Seriously? A scale that omits the root?
If you’re having hesitations about losing the root, think of it this way…
First, the defining feature of a major sound is that the notes you hear are bright compared to the root. (see my brightness & darkness posting). That’s another way of saying that the root is dark compared to the other notes. That being the case, if want a very bright, major sound, and we’re looking to remove notes from the major scale to get a pentatonic scale, the (dark) root is a very sensible choice for removal!
Second, the root is a note that someone else is very likely playing. The bassist, for instance. Unlike many other notes, it’s very likely that if you don’t play it it will still be heard. It may add melodically to what’s going on, but it won’t add harmonically.
Can we go Brighter?
To turn the C pentatonic into the brighter G pentatonic, we replaced its darkest note with the first brighter note available. What happens if we repeat this brightening process on the G pentatonic? We replace the G with an 7#11; the question is one of judgement. Do we want that bright sound? The answer depends on the context and on what we’re trying to project. In modern jazz it is very often an appropriate option; many times in classic jazz too; much less often in older jazz and in pop music and blues., giving us a D pentatonic scale. The is not in the C major scale, but it is part of the brighter C Lydian scale. As a soloist we can almost always use the over a C major chord, even if it is not written as Cmaj
Listen to an example of the D pentatonic scale used over C. Here is our same random pentatonic line, this time transposed from C to D:
…and brighter still?
Can we extend this process one step further? That is, how about if we make the D pentatonic yet brighter?
Observe the diagram of the D pentatonic over C, as well as the next brighter choice, A pentatonic:
Does this sound have any use? Well, let’s listen! Here is our same random pentatonic line, this time transposed from C to A, and still played over C major:
Now we’re entering a more subjective realm, but it’s a sound I personally like a lot. We’ve once again eliminated the darkest note in the scale—this time the ninth (D)—and we replace it with the D. We would normally call this note the flat nine in the key of C. But in the context of so many other bright notes, it actually takes on a super-bright sound. It makes more sense to me to call it a and think of it as a sharp fifteen. Unconventional terminology, perhaps. But that note is the major seventh of the major seven chord based on the ninth. The lower notes in that chord are the nine, the sharp eleven and the thirteen, so I find it sensible to think of it as the sharp fifteen.
We could keep going… the next brighter choice is E pentatonic, which trades the A of the A pentatonic for a. That could be used over a Cmaj7#5 if you want to add the brightness of the sharp fifteen. But the air’s getting a little thin up here, so I’ll leave that for you to experiment with if you like.Sharp 15 over a major chord sounds ridiculous? Think again. Better yet, listen. #JazzTheory Click To Tweet
Pentatonics over Minor Chords
What pentatonic scales we should use over minor chords?
Most minor chords in jazz use the Dorian sound, so let’s start by observing a C Dorian scale:
There are three standard pentatonic scales contained in the seven notes of a C Dorian scale. As we would expect, one of them is the C minor pentatonic. Additionally, there are the G minor and D minor pentatonics:
C minor pentatonic is by far the most common choice to play over Cm7. The other two scales are brighter; they both lack the characteristic minor third (E), replacing it with the 9th (D). The D minor pentatonic additionally replaces the minor seventh (B) with the major sixth (A), thus including only the five brightest notes of the Dorian scale. Listen to the three scales used over C minor:
The C minor pentatonic is the sound we are most used to hearing over C minor, but the others are useable as well— despite their being so bright as to not include the minor third. Note the contrast to the major case, where any pentatonic so dark as not to include the major third was unusable. The bright G minor pentatonic and D minor pentatonic simply include upper extensions of the C minor chord (the 9&11 and the 9&11&13, respectively) in place of primary minor chord tones, creating a more floaty, etherial sound. That makes them useful for “stretching out”—rather than for “digging into” the minor sound.
Going one step brighter gives us the A minor pentatonic. But that is the same as the C major pentatonic, which is to say that it contains E, the major third, and no E. It is of very little use over C minor.
Darker and Darker
Just as we could use progressively bright pentatonic scales over major chords, we have progressively dark scales as options over minor chords:
F minor pentatonic darkens C minor by replacing the fifth, G, with A, the minor sixth characteristic of the Aeolian mode:
B minor pentatonic darkens the F minor pentatonic further by replacing the root, C, with D, the minor second characteristic of the Phrygian mode. Just as we brightened our pentatonic choices over major chords to the point where no longer contained the root, here we have darkened our pentatonic choice over minor until it no longer includes the root:
E minor pentatonic replaces the fourth, F, with G, the diminished fifth characteristic of the Locrian mode, useful over half-diminished chords:
Here we have flattened the five in the accompanying C minor chord to accommodate the G in the pentatonic line—making it a Cm75 half-diminished chord.
The sound may not seem very useful as is because the example vamps statically over the chord. But when we place it in the dynamic context of a minor ii-V-i progression, we can hear its use. Here is Cm75 to F7alt, resolving to Bm. The line over the Cm75 is E minor pentatonic.
A minor pentatonic? What happens if we go one notch darker still? By moving from the E minor pentatonic to the A minor pentatonic, we replace our minor seventh with a major seventh. Nope, that’s too far.
Dominant Chords and Pentatonics:
Not a match made in heaven
Apart from the root, the two essential notes in any dominant chord are the major third and the minor seventh. Since they are a tritone apart, we know they can never belong to the same standard pentatonic scale. After all, standard pentatonic scales contain no tritone pairs. That gives us two choices if we wish to use pentatonics over dominant chords: either sacrifice one of the key notes (the third or the seventh)… or else use a non-standard pentatonic scale.
I’ll deal with the second option at length in a separate blog post. For now let’s consider just the standard pentatonic options.
Here is the C Mixolydian scale, the scale we’d be likely to use to improvise over a basic C7 or C9 chord.
If we look at the three pentatonic scales contained within in C Mixolydian, they are B, F and C:
We can rule out the B and F pentatonics because they contain the fourth (F), an “avoid note,” in place of the major third (E).
Our remaining option, the C pentatonic, contains the major third (E) as well as a number of other basic chordtones of C7 (the root, nine, fifth and thirteen). The problem is… it’s pretty boring! Without the minor seventh it lacks color and tension. We can use it some in static situations, such as over a blues, when we don’t need to emphasize the resolution-seeking quality of a dominant chord. (For instance, see this video by Ralph Bowen.) Still, it doesn’t contain the “bluesiest” note of the Mixolydian scale.
So, the C pentatonic works over C7 but is dull. Darker pentatonics such as B and F don’t work because they contain the fourth (F) instead of the major third (E). How about brighter pentatonics? Unfortunately, those aren’t an option either because the next brighter note B, which we get if we choose the G pentatonic, is the major seventh—a useless alternative to the minor seventh.
Look now at the C Lydian Dominant scale:
Visually, it’s immediately clear that, once again, our only standard pentatonic choice is the C pentatonic, which represents the five contiguous notes in the diagram. It’s an acceptable choice, but it leaves out the two most interesting notes, the bluesy minor seventh (B) and the very bright sharp eleven ( ).
Diminished and whole tone scales
Two other dominant scales are a complete fail for standard pentatonics: The diminished scale, which we use over every C139 chord and, at our discretion, over a number of other dominant chords; and the whole tone scale, which we use over C9+ chords and others. A look at them on the circle of fifths reminds us visually why standard pentatonics won’t work:
Their radial symmetry on the circle of fifths means that they are riddled with “gaps”: the diminished scale has no more than two contiguous notes in a row, and the whole tone scale contains no contiguous notes at all… making for a terrible fit with entirely-continguous pentatonics.
The Altered scale
Observe the C altered scale:
Remember how, when we sought a standard pentatonic scale that included the minor seventh (B), we saw that any option that also included other Mixolydian notes would also have to include the fourth, an avoid note? Well, now we have a chance to use the B by combining it with only darker notes. Namely, the G pentatonic scale, which consists of the five continguous notes in the diagram. These are the minor seven, sharp nine, flat thirteen, flat nine, and flat five. The two absent notes are the root and the major third. It’s still not ideal that the major third is unrepresented, for reasons we’ve spoken of above. But here, in direct contrast to Lydian dominant, the notes represented are the most interesting notes of all the options. Using G pentatonic over a C7alt may not fully convey the dominant-ness of the chord, but it most definitely will convey the its outness and its darkness.
Locrian (Half Diminished)
As a side note, this very darkness of the 75 chord. The only notes absent from the scale are the root and the fourth. And both of those are dispensible… the root because it’s likely to be covered by the bass player, and the fourth because it is not an essential chord tone.pentatonic also makes it a fine choice for Locrian, which we often use over half-diminished chords. pentatonic contains the minor third, the diminished fifth, and the minor seventh of the Cm
Sus chords and pentatonics
Unlike non-sus dominant chords, sus chords are terrific for using pentatonics. In sus chords, the major third becomes an inessential note, replaced by the fourth. Accordingly, the absence of the third-seventh tritone in standard pentatonics is of little concern. The obvious pentatonic approach is to omit the two brightest notes of the C Mixolydian scale—namely, the major third (E) and major sixth (A)—leaving a B pentatonic scale. The notes of that scale are precisely the notes in a C9sus chord, as we can see here:
The “Sus Pentatonic” Scale
So far only two of our pentatonic scales have names: the major pentatonic and the minor pentatonic, which is the fifth mode of the major pentatonic. It makes sense to also speak of the sus pentatonic scale, which is the second mode of the major pentatonic scale:
And observe the C sus pentatonic compared to the C major pentatonic. It is the second mode of the B pentatonic scale:
We can also see that the scale contains the same notes as a G minor pentatonic. It is natural that the G minor pentatonic scale has a sus sound when played over C, because Gm7/C is the same as C9sus. (See my previous post on sus chords.)
Incidentally, we saw the sus pentatonic earlier, in our discussion of minor options. As a possible choice for C minor, we spoke of using the G minor pentatonic—which is to say, using C sus pentatonic. We observed that it gave a floaty sound that emphasized the upper extensions. The absence of the minor third is all that distinguishes the C9sus sound from the similar Cm11… so it is no wonder that the sus pentatonic, which contains no third at all, can be used over either.
The Remaining Pentatonic Modes
The two remaining modes of the major pentatonic scale are the third and fourth modes.
The third mode starts on the major third, which is the brightest note of the pentatonic scale (the furthest clockwise on the circle of fifths). As a result, all the other notes are dark by comparison, making this the darkest mode of the major pentatonic. We saw it above; it is just like the minor pentatonic, but with its fifth raised to a become a minor sixth instead. Because of that minor sixth, we could call it the Aeolian Pentatonic scale.
The fourth mode starts on the perfect fifth of the major pentatonic. Its notes are the root, second, fourth, fifth and sixth. It is a major pentatonic but with the third raised to become a fourth – not a very useful sound in jazz.
Summary of Uses
Here is a summary list of the pentatonic scales that can be used over a C chord and their uses…listed from darkest to brightest.
(dark to bright)
|G||G, D, A, E, B||D, E, G, A, B||Cm75 • C7alt|
|D||D, A, E, B, F||D, E, F, A, B||Cphr.|
|A||A, E, B, F, C||C, E, F, A, B||Cm6|
|E||E, B, F, C, G||C, E, F, G, B||Cm7|
|B||B, F, C, G, D||C, D, F, G, B||C7sus • Cm11|
|F||F, C, G, D, A||C, D, F, G, A||F/C|
|C||C, G, D, A, E||C, D, E, G, A||C • C7|
|G||G, D, A, E, B||D, E, G, A, B||Cmaj7|
|D||D, A, E, B, F#||D, E, F#, A, B||Cmaj7#11|
|A||A, E, B, F#, C#||C#, E, F#, A, B||Cmaj7#11(#15)|
|E||E, B, F#, C#, G#||C#, E, F#, G#, B||Cmaj7#5(#15)|
I’ve left out the B major pentatonic because it seems to me it doesn’t have much use over C. Maybe I should have left out E as well—that’s not going to be of much general use either. Though, of course, in the right hands and in the right context, almost anything can be used well over anything.
Ok, this post turned out longer than I imagined. But there’s still a lot more to talk about. Stay posted for a part two…