The CAGED system is a powerful tool for memorizing scales, modes, arpeggios, and chords across the guitar fretboard. In this blog post, we’ll enhance the CAGED framework by layering interval analysis on top of it—unlocking its full potential for mastering harmony and improvisation.
Chromatic Intervals Within Octave Shapes
As introduced in the previous post, we can locate every interval by examining the chromatic notes that exist between two reachable root notes (octaves). The fact that all musical intervals can be found within these two compact octave shapes means that virtually all melodic, harmonic, and chordal structures exist in a limited number of repeatable, ergonomic forms on the guitar.
This makes the guitar a uniquely convenient instrument for executing complex harmony, particularly in modern music genres.
Deriving the 5 CAGED Shapes of the C Major Triad
Let’s revisit how the five CAGED shapes for the C major triad can be derived step by step:
- Understand the triad formula: A major triad consists of a root (C), major third (E), and perfect fifth (G).
- Map intervals in octave shapes: Using the two reachable octave shapes, identify all the E and G notes relative to each C root. These define two arpeggio shapes for the C major triad.
- Stack to form all five positions: By layering the two octave shapes in different regions of the fretboard, we arrive at five distinct CAGED positions.
- Refine for playability: To make the shapes practical on guitar, some chord tones on the same string may need to be omitted or reordered.
Step 2
Step 3
Step 4
A. Applying This to Arpeggios, Scales, and Modes
Following the same logic (Steps 1–3), you can construct five CAGED positions for: - Any arpeggio - Any scale or mode
Once the intervals are mapped, stacking them systematically reveals the full fretboard coverage.
B. Applying This to Chords
For chords, you’ll need to add Step 4—optimizing for playability. Most standard chords will yield at least 2 to 3 ergonomic shapes, depending on complexity.
For extended or complex chords (e.g., maj13, m11b5), you may need to prioritize the most important chord tones—such as 3rds, 7ths, or tensions—based on the musical context.
Example: Dorian Mode Through the CAGED Lens
Let’s take a closer look using the Dorian mode as an example.
We know the D Dorian scale contains the following intervals:
R, 2, b3, 4, 5, 6, b7
Using our two octave shapes, we can derive two compact Dorian scale forms that contain all these intervals.
Next, we stack the two shapes, adjusting for the G–B string tuning shift, and align them across different positions anchored to the D root. The result? Five well-defined CAGED shapes for the D Dorian mode.
Expanding the CAGED System Beyond Major Harmony
You may notice that these Dorian shapes look identical to the C major CAGED shapes, only with swapped shape names. So why rename the shape?
Because while the shapes are the same geometrically, the harmonic content is entirely different:
- The C major shapes reflect major harmony, containing intervals such as R, 2, 3, 4, 5, 6, 7.
- The D Dorian shapes are rooted in minor harmony (b3, b7), with characteristic intervals like 6
This distinction becomes especially important in contexts like: - Modal playing - Non-diatonic harmony - Jazz and modern pop, where modulation is frequent
By redefining these shapes in terms of their modal interval structure, you train your brain and fingers to think harmonically, not just visually.
Final Thoughts
With interval awareness layered into the CAGED system, we can finally extend it beyond major harmony, and apply it to:
- Minor chords and arpeggios
- various scales including pentatonic, blues scales, minor family scales and various modes
- transitions between parallel modes and scales
- improvization and harmonic analysis
Stay tuned for the next part!