Explore how to systematically understand, build, and memorize guitar chords using interval logic and the CAGED system.
Recap
In a previous post, we introduced the CAGED Interval System as a three-step method for navigating the fretboard:
- Identify root notes using two reachable octave shapes.
- Divide the fretboard into five CAGED positions based on which strings the root notes occupy.
- Select chord tones within those positions to construct chord, arpeggio, and scale shapes.
This post begins a new series applying the system to real-world musical structures—starting with chords. The CAGED Interval System is especially powerful for analyzing and organizing all kinds of harmonic material, from basic triads to rich jazz chords. It enables guitarists to quickly visualize playable shapes around specific root notes, which is vital in modern genres heavily influenced by jazz harmony.
One key insight we’ll explore: how different chord types with the same root vary across the five CAGED positions. Through this comparison, you’ll gain a deeper understanding of how intervals move and interact within the system.
How to Systematically Memorize Guitar Chords
Guitarists often feel overwhelmed by the vast number of chord shapes. But the good news is—you don’t need to memorize them all.
Instead, focus on a core set of triads and seventh chords. These foundational “workhorse” chords form the basis of most progressions and appear in countless styles. Once mastered, they provide a reliable framework from which you can derive extended and altered voicings.
Using the CAGED Interval System as your foundation, it becomes much easier to learn and recall these essential shapes. Need to play a 9th, 11th, or 13th chord? Simply locate the added interval relative to your CAGED shape and modify accordingly. This transforms the memorization of hundreds of chords into a logical, interval-based system.
Basic Triads and 7th Chords
Triads
A triad is built from three notes spaced by major or minor thirds. There are only four types of triads:
| Interval Structure | Triad Type |
|---|---|
| Major 3rd + Minor 3rd | Major Triad |
| Minor 3rd + Major 3rd | Minor Triad |
| Minor 3rd + Minor 3rd | Diminished Triad |
| Major 3rd + Major 3rd | Augmented Triad |
C Major Triad
The C major triad is where the CAGED system begins. Below are the five CAGED positions for a C major triad, which you’ve likely seen many times.
C Minor Triad
Due to ergonomic limitations, the A, E, and D shapes are the most commonly used for minor triads. These are derived from the open chords Am, Em, and Dm, with the index finger acting as a movable capo.
The C and G shapes are less practical because they require awkward fingerings—especially when reaching for the minor 3rd. Below is one way to visualize C minor triad in five CAGED positions.
C Diminished & C Augmented Triads
Diminished and augmented triads are used less frequently and don’t need to be prioritized early on. However, it’s useful to understand their structure and recognize their CAGED forms.
- For C diminished, only three positions are reasonably playable due to the awkward interval between the b5 and the next root.
- C augmented is a symmetric chord built entirely on major thirds, so the A and E shapes are identical in form, though the root lies on different strings.
Common 7th Chords
Seventh chords are formed by adding a 3rd interval above a triad, resulting in four notes. These are the basis for more advanced harmony.
Why focus on 7th chords?
- They’re prevalent in modern music
- They’re often easier to play than triads
- They help anchor extended tones like 9ths, 11ths, and 13ths
Use them as your foundation: - Omit the 7th for a triad - Add to form extended chords
Let’s examine four common 7th chord types—all rooted in C—across the CAGED positions.
Cmaj7
Cm7
C7 (Dominant 7)
Cm7♭5 (Half-Diminished)
Other 7th Chords
We’ll explore additional 7th chords (e.g., Maj7♯5, Dim7) in a future post.
Extended and Suspended Chords
Extended chords include tones beyond the 7th—namely the 9th, 11th, and 13th. These add color and tension to chords.
Rather than deep-diving into theory here, we’ll focus on how to find and build these chords using the CAGED Interval System.
Two Strategies:
- Note Addition – Start with a 7th chord and add interval notes based on the CAGED system.
- Upper Structure – Play the “top half” of a more complex chord. For example, Cmaj9 can be built from an Em7 shape (the upper structure), omitting the root C.
Adding 9th, ♯11th, and 13th to Cmaj7
Below are visuals of Cmaj7 with added 9th, ♯11th, and 13th intervals.
Upper Structure: Em7 over C = Cmaj9
Here’s how you can play Cmaj9 by using the Em7 shape and omitting the root C.
Other Extended and Suspended Chords
There are countless other chord types—altered dominants, suspended chords, hybrid voicings, etc.
The good news: you don’t need to memorize them all.
Instead, use: - Common 7th chords as the foundation - CAGED interval logic to locate and build - Your ear and theory knowledge to guide choices and omissions of chord tones
With a solid grasp of the CAGED Interval System, you can construct nearly any chord on the fretboard.
A Quick Summary
In this post, we explored how to apply the CAGED Interval System to a wide range of chord types—from basic triads and 7th chords to more advanced extended voicings.
The key takeaway: once you internalize the structure of intervals within each CAGED shape, you’re no longer limited to memorized fingerings—you gain the freedom to build, adapt, and create chords based on real musical understanding.
Stay tuned for future posts where we’ll explore modal chords, voicing variations, and harmonic analysis using the same interval-driven approach.