Every rock-influenced guitarist learns the major pentatonic and minor pentatonic scales early on. The mileage you can get from those two scales alone is endless. Furthermore, it's not uncommon to substitute different pentatonic scales over the same harmony. One might throw in some A minor pentatonic licks over Dm, emphasizing E, the 9. I've heard many jazz players use and speak of superimposing pentatonic scales over more complex harmonies. But I've taken it beyond substitutions and superimpositions; I regard pentatonic scales as fundamental to my playing.

The three elements commonly used to understand music are chords, arpeggios, and scales. Unless you're dealing with really crazy or "world" music, the scales used are almost exclusively 7-note scales: modes of the major scale, melodic minor, harmonic minor. (The whole-tone, half-whole diminished, and whole-half diminished scales are the three exceptions. Even harmonic major, for the crazies, has seven notes.) Mastery of music created in this manner (most of Western music) requires the ability to translate quickly between chords, arpeggios, and scales.

Pentatonic scales sit between the (usually 4-note) arpeggios and (usually 7-note) scales above. I use them as much for visualization on the guitar fretboard as for note generation and theoretical analysis.

The Other Pentatonic Scale

The major and minor pentatonic scales are modes of each other, so I consider them as coming from the same source. For simplicity, I'll use the major pentatonic as the parent mode.

But there's another option. I wrote about it a long time ago: The Other Pentatonic Scale. I've taken to calling it the "dominant pentatonic scale", as that's how I use it most. Its notes are 1 2 3 5 b7, or over G7, G A B D F. There are many different ways to use this scale, but again for simplicity, I'll use the dominant pentatonic as the parent mode.

(Incidentally, the modes of the major pentatonic and dominant pentatonic are the only possible 5-note scales consisting of only major seconds and minor thirds. See How Many Scales Are There? if this fascinates you.)

Pentatonic Assignments

In my last post, I discussed the 10 Types of Jazz Chords I consider when improvising in jazz. This is my primary focus in using pentatonic scales, to embellish and improvise upon established chord progressions. Below is a list of which pentatonic I assign by default to each of these 10 categories. More than one will fit in nearly every case, but I limit my starting point in each category to a single pentatonic scale.

• 6 (69, major triad)
  maj pent on 1: 1 2 3 5 6
• maj7 (maj7b5, maj13#11, Lydian)
  maj pent on 5: 2 3 5 6 7
• 7 (13#11, Lydian Dominant)
  dom pent on 1: 1 2 3 5 b7
• 7sus (Mixolydian)
  maj pent on b7: 1 2 4 5 b7
• 7b9 (13b9, natural 5, symmetrical dominant)
  (No pentatonic fits. Use dim arp on 3.)
• 7alt (altered 5s and 9s, altered dominant)
  dom pent on b5: b2 3 b5 b6 b7
• m7 (more ii than i, Dorian)
  maj pent on b3: 1 b3 4 5 b7
• m6 (tonic minor i, melodic minor, m/maj7)
  dom pent on 4: 1 b3 4 5 6
• m7b5 (m9b5, Locrian Natural 2)
  dom pent on b6: 1 b3 b5 b6 b7
• dim7 (symmetrical diminished)
  (No pentatonic fits. Use dim arp on 1.)

Pentatonic Visualization

Now, don't jump to assume that basing your playing on pentatonic scales will make your playing sound forever pentatonic. Practicing arpeggios doesn't make your playing sound unnecessarily arpeggiated unless you don't progress beyond arpeggios. Likewise, pentatonic scales are just a starting point for achieving whatever sounds you want to.

The primary advantage on guitar is visualization. All of these pentatonic scales are most easily played two notes per string in any of the standard CAGED positions.

C Major Pentatonic:

C Dominant Pentatonic:

Any advanced guitarist with experience in rock or pop is as familiar with the five positions of major pentatonic as a fish is with water. Using them as a basis for understanding other chord types is a huge advantage, because you deal with all the old familiar shapes and fingerings. The dominant pentatonic, on the other hand, is far less common. The only reference I've heard about it being a useful scale in its own right is from a Robben Ford instructional video. He used a different mode, from the "m6" category above (1 b3 4 5 6), creating a Dorian sound over a m7 chord. Other than that, I've never heard of someone using this scale the way I do, so it's probably a minor hurdle to learn it as well as one knows the major pentatonic. But there are only five positions to memorize; it didn't take me long.

Using the specific pentatonic scales above, many standard jazz progressions take on a simple beauty. In a I-vi-ii-V progression, the prescribed pentatonics differ by only one note between consecutive chords. (See Pentatonics over Jazz Chords.) And alternative perspectives on harmony tend to reveal themselves a little easier. The pentatonics for Imaj7 and iiim7 are identical, so I-vi-ii-V and iii-vi-ii-V are treated the same. A progression like the following snippet from "Just Friends" doesn't immediately tell you that you can move the same lick down by half steps through all three measures.

Bbm7 Ebm7 | Fmaj7 | Abm7 Dbm7 |

But when you begin these three measures with Db major pentatonic, C major pentatonic, then B major pentatonic, you'd have to be asleep to avoid utilizing this chromatic descent in your improvising.

Finding Arpeggios and Scales

Pentatonic scales sit between arpeggios and the standard 7-note scales. You can use any pentatonic scale as a starting point for finding either the appropriate arpeggio or 7-note scale. Drop one note for a 4-note arpeggio, or add two notes for a 7-note scale. The key is knowing which notes to drop or add. For example, over C7alt, I start with the appropriate pentatonic: b2 3 b5 b6 b7 = Db E Gb Ab Bb (equivalent to Gb dom pent). I can drop Gb for a nice Bbm7b5 arpeggio, or I can drop Ab for a Gb7 arpeggio, or I can add C and Eb to complete the altered dominant scale.

In one of my first blog posts on From the Woodshed, I explained my theory of Constructing Jazz Scales from Chord Tones, in which I arrive at the generally agreed-upon "most consonant scale" for every chord type by adding the note a whole tone above the 3, 5, and 7 of any kind of 7th arpeggio. The same principle applies to every one of the pentatonic scales above (with one exception), even the two diminished arpeggios when no pentatonic works. An easier way to see it is to add the higher of the two skipped notes in any minor third. C dominant pentatonic (C D E G Bb) has minor thirds between E and G and between G and Bb. Therefore, add F# and A, and you get the "most consonant scale", Lydian Dominant. Try it with the others; it works every time (almost).

The one exception is the maj7 category. Using this rule adds #4 and #1 (instead of the root) to the scale. Sense can be made of this if you consider going "Double Lydian", another concept I discovered in the early days of this blog in the post Beyond Conventional Extensions. I encountered the name in a class at SDSU, and employed it in one of my compositions, The Kármán Line.

Pentatonic Tricks

There are all sorts of tricks that can be used with pentatonic scales on the guitar. I feel like I discover a new one every few months.

Pentatonic Sweeps
I wrote about Pentatonic Sweeps a few years ago. I'll demonstrate it more completely one of these days once I'm halfway decent at it.

Legato
Since all of these are two notes per string, you can burn straight up and down by picking the first note and hammering-on or pulling-off the second. Your pick can run through all six strings like a sweep while your left hand does most of the work.

Sequences
Any kind of sequence will work fundamentally the same way between different pentatonic scales, again because they're all two notes per string. The picking pattern is necessarily identical.

Mimic a Motif
Want to apply variation to a theme? No problem! Visualize your theme on the appropriate pentatonic scale, and apply it to a different area of the same scale or to a new scale if the harmony has changed. Did I mention "two notes per string"? They're all the same! There's a low note and a high note on the sixth string, a low note and a high note on the fifth string, etc. Take one idea and apply it in dozens of different ways without changing the underlying fingering.

Bebop-ish Scales
Bebop Mixolydian adds the natural 7 to the standard Mixolydian scale, allowing a player to run straight through the scale with only chord tones on the down beats. Since every note in one of these pentatonic scales is a strong tone (if not a chord tone), you can do the same thing by adding in-between notes on the upbeats. They can be chromatic or derived from the appropriate 7-note scale, but you have many options beyond the 8-7-b7 descent of Bebop Mixolydian.

Get Outside
With pentatonics, I have two quick strategies to introduce spurts of outside sounds in my playing. Since the most magnetic of chromatic notes is a semitone below the target note, why not play a succession of these little leading tones? Momentarily switch to the pentatonic scale a half step below the one you're working with and back again. It twists the ear and snaps it back like a rubber band. I got the second trick from harmonizing bebop lines in an arranging course at SDSU. Take a moment to imply the V7alt of the chord you're playing over. Since I'm most familiar with the root mode of the dominant pentatonic, this translates to playing the dom pent a half step above the current root note. Make sure it resolves before the next chord comes up.

Explore

I've written a handful of articles on pentatonic scales in the past. It's an obsession. In addition to the content linked to above, check out Strange Uses for Pentatonic Scales, Pentatonic Slides, and SDSU Oral Exam: Analyzing My Own Solo.