Explore how to systematically understand, construct, and memorize guitar scales and modes using interval logic and the CAGED system.
Recap
In the previous post, we explored how to use the CAGED Interval System to build arpeggios for triads, 7th chords, and even extended chords. Building on that foundation, it only takes a few simple steps to construct scales and modes from those arpeggio shapes.
In this post, I’ll walk you through an efficient method—used by many professional guitarists—to organize and internalize scales and modes within the CAGED framework. We’ll focus less on music theory and more on practical fretboard mastery.
Building Scales from Arpeggios
Major Modes from Major Triad Arpeggio Positions
We already know how to map major triad arpeggios across five CAGED positions. From there, it’s a small step to add additional scale degrees—such as 2nds, 4ths, 6ths, and 7ths—to form complete major scales and modes.
For those less familiar with modes, here’s a simple explanation. Modes are alternate versions of the major scale that shift the interval structure. They are incredibly useful for composition and improvisation. When you hear a melody shift into something dreamy, edgy, or exotic, there’s a good chance a mode was introduced.
To hear the effect clearly, try playing the C major scale, then try C Lydian or C Mixolydian—you’ll notice certain notes stand out. These changes are subtle but powerful. Here’s a comparison of their intervals:
| Name | R | 2nd | 3rd | 4th | 5th | 6th | 7th |
|---|---|---|---|---|---|---|---|
| Major | R | 2 | 3 | 4 | 5 | 6 | 7 |
| Lydian | R | 2 | 3 | #4 | 5 | 6 | 7 |
| Mixolydian | R | 2 | 3 | 4 | 5 | 6 | b7 |
Rather than memorizing all three sets of positions for major, Lydian, and Mixolydian, you can simply memorize one—the major scale—and then adjust the relevant degree: - Raise the 4th for Lydian - Lower the 7th for Mixolydian
Below are the five CAGED positions for each, with key differences highlighted.
Minor Modes from Minor 7th Arpeggio Positions
Following the same logic, you can use minor 7th arpeggios as the foundation for minor scales and minor modes.
| Name | R | 2nd | 3rd | 4th | 5th | 6th | 7th |
|---|---|---|---|---|---|---|---|
| Minor | R | 2 | b3 | 4 | 5 | b6 | b7 |
| Dorian | R | 2 | b3 | 4 | 5 | 6 | b7 |
| Phrygian | R | b2 | b3 | 4 | 5 | b6 | b7 |
These modal flavors can be easily added to your fretboard vocabulary by modifying just one or two notes.
Other Scales
The same thought process can be applied to most scales—as long as you understand the interval structure of the scale, you can easily map out its five CAGED positions. This approach allows you to organize nearly any scale within the CAGED framework and quickly identify scale tones across different areas of the fretboard.
That said, the CAGED Interval System isn’t always ideal for symmetric scales like the diminished or whole tone scales. These scales repeat at regular intervals and inherently contain fewer unique positions: - The diminished scale only has three distinct shapes before repeating. - The whole tone scale contains just one repeating shape across the fretboard.
Because of this symmetry, it’s not necessary—or even practical—to map out all five CAGED positions. Instead, recognizing the repeating unit of the scale and shifting it accordingly will give you more efficient fretboard coverage.
Discussion: Shifting Shapes vs. Interval Thinking
You may have noticed that major and minor scale shapes are identical when played three frets apart. This is why many guitar teachers suggest the trick of “shifting the same lick up or down three frets”—it’s an effective shortcut to explore both major and minor tonalities, especially in blues.
Let’s compare two mindsets when switching modes or tonal centers:
1. CAGED Shape Thinking
You keep the shape and shift it up or down the neck. For example, to play C Minor on top of C Major, you shift the C Major scale shape up 3 frets.
2. CAGED Interval Thinking
You keep the root fixed and change the intervals. For C Minor, you think of Cm7 arpeggio in the same position, and map out the C Minor scale with 3 additional scale tones.
But when it comes to modal interchange, this trick doesn’t always cut it. Here’s a few more examples of comparison, you will find CAGED Shape Approach tricky to conduct so many calculation on the go:
| Progression | CAGED Shape Approach | CAGED Interval Approach |
|---|---|---|
| C minor → C Dorian | Play G minor shape 5 frets lower | Raise the 6th in C minor scale |
| C mixolydian → F mixolydian (blues vamp) | Shift 5 frets higher from F major to Bb major | Think F7 arpeggio, map F Mixolydian intervals |
| C major → F melodic minor (I-iv modulation) | Use Ab major shape and modify intervals, or play F major shape with flat 3rd | Think FmMaj7 arpeggio, map F melodic minor intervals |
CAGED Shape thinking works well when your song stays in one key or has blues-style movement. But in modal and jazz contexts, where harmony changes often, CAGED Interval Thinking is far more adaptable.
Which Is Better?
It depends on the musical context.
- If you’re playing blues or rock and sticking to one root for many bars, shifting shapes is fast, intuitive, and requires less practice.
- But for modern pop, jazz, or fusion, where the harmony changes quickly and subtly, interval-based thinking helps you stay connected to the muscial context and navigate changes smoothly.
In short, both are useful—but CAGED Interval Thinking offers more control and versatility for advanced musicianship.
What’s Next
In the future posts, we’ll use the CAGED Interval System to visualize modal interchange, analyzing how to shift from one mode to another smoothly on the fretboard.
Stay tuned—it’s where theory meets improvisational fluency!