A pentatonic and hexatonic scale primer
Communication in music is an interesting topic. For example, when talking to other musicians and you refer to the “pentatonic scale”, it’s widely understood what’s meant by that. In most circles you’re specifically talking about the minor pentatonic scale, or in intervals a root, b3rd, 4th, 5th, and b7th. This is a sound you’ll have heard extensively in any western blues rooted music, it’s one of the building blocks or rock and metal music.
However, if we take a step back and look at the word pentatonic, it s a combination of the Greek prefix penta (meaning five), and the suffix tonic (meaning the 1st note of the major scale, or tone/sound) we can see that the name really just means a scale with five notes. If my calculations are correct, this means there are 330 possible groupings of 5 notes that can be found in our 12-tone system… that might seem like a lot, but it’s also a mind numbingly finite number, especially when you consider that a large swathe of those scales are functionally useless to us.
I wanted to bring that to your attention to help us consider that there are many pentatonic scales we can draw from. Now you know you can, let’s talk about why you might do that. Why not just play a full major scale? Why limit ourselves to just 5 notes?
One possible answer lies in the sound different intervals have. Play the note C followed by D is a 2nd, and it sounds a certain way, but playing the note C followed by G is a 5th and this sounds a completely different way. When drawing melodies from scales, it’s common to move up and down by scale degree (known as conjunct movement), and this means you’ll rarely hear intervals that aren’t major or minor seconds as all notes in the major scale are close to each other.
The major pentatonic
When we take a collection of notes like the C major scale
C D E F G A B
And remove some notes to create the C major pentatonic scale
C D E G A
Now we have some slightly bigger leaps between the notes E to G and A to C.
Now if you play a longer scale based run, it’s not going to have the same step wise sound of the major scale.
The other reason is certainly intervals and tension notes. It’s no accident that the C major pentatonic scale is missing the F and B, these notes are the 4th and 7th respectively and they sound the most jarring over a C chord. They’re not “wrong” notes, but they’re certainly “avoid” notes as landing on either of these notes over a C chord will really sound out of place.
So playing the pentatonic scale really lowers the risk of landing on a bad note. This always seemed like the most important reason to me. And it applies to the minor equivalent too.
The minor pentatonic
Here we have the A minor scale
A B C D E F G
And here’s the A minor pentatonic scale
A C D E G
The pentatonic scale is missing the B (2nd) and F (b6th) and while the 2nd is a wonderful colour tone on a minor chord, the b6 is a really dark sound. In fact, it’s quite a risky note as the difference between the dorian and aeolian mode is that 6th. So playing a scale that doesn’t contain that note means your licks will work in either context.
When looking at other pentatonic scales, you’ll often see the term “exotic scales” thrown around, but in reality, it’s a very western way of naming things, calling a scale Indian or Japanese based on the sound rather than any real academic underpinning. In fact, if you look online you’ll probably find many different collections of notes attributed to some of the following names.
For each of these scales I’ll give you the notes in the key of C, and then the intervals from the root. This should help you see chords and flavours.
C Hirajōshi pentatonic
C D Eb G Ab
1 2 b3 5 b6
Looking at this scale we can see a minor triad (1 b3 5) with the added 2 and b6. A favourite of players like Jason Becker and Marty Friedman
A close relative would be the Kumoi pentatonic, one that I’ve seen many spellings for! C Kumoi pentatonic
C D Eb G A
1 2 b3 5 6
This one is very similar to the Hirajōshi, but now featuring a 6 instead of the b6. It could also be seen as the major pentatonic with a minor 3rd, or perhaps a pentatonic coming from the dorian or melodic minor scales. Rogan/Indian pentatonic
C E F G Bb
1 3 4 5 b7
Another interesting sound that George Harrison was notable for toying with. It’s like a minor pentatonic but with a major 3rd, or a stripped back version of the mixolydian mode.
One final pentatonic I’d like to highlight is the minor 6 pentatonic
C minor6 Pentatonic
C Eb F G A
1 b3 4 5 6
This is a minor pentatonic scale with the b7 lowered down to the 6th. Robben Ford is a big fan of this particular pentatonic scale.
Now with our explorations into the construction and possibilities of pentatonic scales briefly covered, let’s talk hexatonic scales!
The astute among you will have anticipated the meaning of the word, with hex- meaning six. These are 6 note scales, and they’re a lot more common in music than you might think!
As with pentatonic scales, hexatonic scales can be thought of as either pentatonic scales with an added colour, or full diatonic notes with an avoid note removed.
Naming conventions for hexatonic scales are a little bit patchy, but for the most part I tend to describe them in terms of pentatonic scales with added notes. For example
C minor pentatonic
C Eb F G Bb
1 b3 4 5 b7
C minor pentatonic add 9
C D Eb F G Bb
1 2(9) b3 4 5 b7
As a sound, this scale is extremely common in popular music. The minor pentatonic scale is ubiquitous in music, and the 2nd (or 9th) is a wonderful colour to add to a pentatonic scale. You’ll hear this extensively in the playing of the likes of Eric Johnson, Joe Bonamassa, Slash, and many more.
You could even think of the blues scale as a hexatonic scale
C blues scale
C Eb F Gb G Bb
1 b3 4 b5 5 b7
To me this highlights why we think of these as an added note approach. You probably already know the blues scale, but I’d be surprised if you think of it as a new scale, rather than the pentatonic scale with an added note.
In my module of pentatonic mutations I highlight some of my approaches for turning pentatonic scales into hexatonic ideas by exploiting the guitars tuning and our 2 note per string system for pentatonic patterns. On the guitar, it’s easy enough to switch out one of the pentatonic notes for another note on the same string.
One of my biggest influences in this area is my long time friend Andy James, one of the masters of modern shred guitar, and someone who likes to mutate his pentatonic patterns all the time. One not to miss!
To me there’s nothing more exciting to get the creative juices flowing than to sit down at my guitar and come up with new 2 note per string patterns for string crossing, looking to tap into some of these exciting pentatonic and hexatonic scales, and break away from the tired old scale runs of rock and metal guitar from days gone by!