I'm sure that if you're reading this, you're well aware of what the pentatonic scale is and I'm sure you're likely even experienced at using it for improvisation. Despite your familiarity with this scale, what I'd like to do in this article is inspire some creativity in your playing by using this one scale that we all talk about to the point of exhaustion as sort of a common ground starting point where I can get my foot in the door on the topic of music theory in a way that hopefully comes across as fun and interesting. Who knows, maybe I can direct you towards some unconventional ways of thinking about pentatonic scales that might challenge your playing!
Let's start by breaking down what exactly the pentatonic scale is first. Broadly speaking, when guitarists refer to the pentatonic scale they are referring to the minor pentatonic scale. In order to explain where the minor pentatonic scale comes from, I must first explain where the major pentatonic scale comes from, as the minor pentatonic is derived (I will explain how) from the major scale.
The Major Pentatonic Scale
The quickest, easiest response to the question "Where does the major pentatonic scale come from?" is that it comes from the major scale. Let me elaborate a bit. The major scale in the key of C goes like this: C, D, E, F, G, A, B, C. All we have to do to turn this scale into a major pentatonic scale is remove the fourth note (F) and the seventh note (B). This turns our seven note scale into a five note scale (hence the name pentatonic). In the key of C it would look like this: C, D, E, G, A. Importantly, this scale gets rid of those pesky fourth and seventh notes which can sound kind of spicy if you're not sure how to use them when you're improvising. This makes for an easy to use scale that we can incorporate into lots of different improvisational contexts.
The Minor Pentatonic Scale
As I mentioned earlier, the minor pentatonic scale is derived from the major pentatonic. But how?! All you need to do to derive the minor pentatonic from the major pentatonic is to take any major pentatonic scale and start it on the fifth and last note of the major pentatonic scale. In the example we used above with the C major pentatonic scale, this would mean starting the scale on A, which is the fifth and last note of the C major pentatonic scale. Doing this results in a scale that looks like this: A, C, D, E, G. If you take a look at this on your fretboard, you will see that playing this across two octaves on your guitar starting on your fifth fret playing two notes per string will result in that all too familiar minor pentatonic scale shape.
So What?If this is all old information, I urge you to keep reading because the implications of the process creating these two scales are bigger than you might expect. Firstly, this means that for every major pentatonic scale there is a minor pentatonic scale that shares the same exact notes, and vice versa. For anyone who is familiar with the concept of relative minor and relative major keys, this is essentially that. In very guitartistic terms, this means that there are two shapes (the major pentatonic shape and the minor pentatonic shape) that we can use now instead of just one. For example, if we're playing a blues in the key of A, we can use the tried and true A minor pentatonic shape, but we can also use the relative major C major pentatonic shape because this is the exact same group of notes. To expand this same idea even further, try googling "the five shapes of the minor pentatonic scale". If you do a google image search, you will see that these five shapes connect and allow you to play any major or minor pentatonic all the way across your fretboard.
Extracting a Formula
Here's some more food for thought. For those of you who are familiar with modes, or anyone who knows a few scales that this can be applied to, there is a formula for creating a pentatonic scale here that can be expanded and used to create a huge amount of new and likely not often used pentatonic scales.
Just like creating the major pentatonic scale from the major scale, let's see what taking the 4th and 7th notes out of some other scales might give us. Consider for example, a C melodic minor scale: C, D, Eb, F, G, A, B. If we remove the 4th note (F) and the 7th note (B) we're left with something that looks like this: C, D, Eb, G, A. This is a pretty funky sounding pentatonic and is well suited for a major blues because unlike the typical minor pentatonic scale, this scale contains the 3rd degree of the IV chord.
Extracting ANOTHER FormulaAre you still with me? OK good, I promise I'm almost done with this. I have one final thought to add into the fold here. If we go back to the original minor pentatonic scale, the one derived from the major pentatonic, we can actually take from that scale another formula for creating a pentatonic scale. In the example from the beginning of this article we looked at A minor pentatonic, which we got by taking C major pentatonic and starting it on its fifth and last note (A) giving us this: A, C, D, E, G.
HOWEVER, for anyone who knows about modes and key signatures, consider this. If you're aware that in the key of C the mode that starts on A is an A Aeolian mode, lets look at what happens when we compare an A Aeolian with our A minor pentatonic scale. A Aeolian looks like this: A, B, C, D, E, F, G and A minor pentatonic looks like this: A, C, D, E, G. So, it can be said that A minor pentatonic is like an A Aeolian mode without it's 2nd and 6th notes. Here we have another formula we can try to apply to other scales!
Let's take our C melodic minor scale again and put it through this formula. As we know, C melodic minor looks like this: C, D, Eb, F, G, A, B. If we take away the 2nd note (D) and the 6th note (A), we are left with a pentatonic scale that looks like this: C, Eb, F, G, B. This is a pretty dark sounding scale, and would work great in a song that resolves to a minor key. It's also a fairly unconventional sound all things considered. Finally, what would happen if like our major pentatonic scale, we took this scale and started it from it's fifth and last note (B)? We would be left with a scale that looks like this: B, C, Eb, F, G. This scale is pretty crazy! It's almost like a whole tone scale with a b2 and no 7th. This could be a pretty great sound over an altered dominant chord, or over a V chord that is resolving back to I.
I should say before finishing this that none of these ideas were invented by me. There are tons of musicians who have contributed to the study of pentatonics, but perhaps the most widely known is saxophonist Jerry Bergonzi.
This method book is very helpful for guitarists seeking to understand Bergonzi's approach to the use of pentatonics. Bergonzi is known for using digital patterns that are very applicable to the guitar and for combining different pentatonics together as well as using pentatonics derived from other scale degrees of a given chord than just the root. These are concepts not discussed specifically in this article but will nevertheless develop your understanding and approach to pentatonics.
Please feel free to comment or to reach out to me with any questions or criticisms about this article! Thank you as always for making me a super small part of your development on the guitar, it's something I never take for granted :)