Electric Guitar, Part 2: The CAGED Fretboard

Music Theory Fundamentals for Producers

Essential music theory concepts for electronic music producers covering scales, chords, progressions, rhythm, basslines, and melodic writing — with practical applications for modern production.

Part 1 covered the hardware — body shapes, pickups, woods, amps. This part covers the other half of the instrument: the geometry under your fingers. One fretboard, five shapes, everywhere.

• Part 1 — body shapes, pickups, and the amp chain
• Part 2 — this page: the CAGED system and the pentatonic overlay.
• Part 3 — studio and workbench

The CAGED system: five major scale shapes named after the open chord shapes C, A, G, E and D

The CAGED System: Unlocking the Fretboard ⭐⭐

The CAGED system organizes chord shapes across the fretboard based on five open-position chords: C, A, G, E, D. Each shape connects to the next, covering the entire fretboard.

The five open shapes themselves are the anchor — learn them as chords first, then move them:

Open major chord shapes: C, A, G, E and D in open position

The Five Shapes

C Shape: Root on A string (5th fret), second finger forms C shape. Connects to A shape.

C Major - Open Position (0-3 frets)
e|---0---|---|---|  (E) - 3rd
B|---1---|---|---|  (C) - Root
G|---0---|---|---|  (G) - 5th
D|---2---|---|---|  (E) - 3rd
A|---3---|---|---|  (C) - Root
E|---X---|---|---|  (Muted)

C Shape at 3rd fret (Root on A string)
e|---|---|---3---|  (G) - 5th
B|---|---|---5---|  (C) - Root
G|---|---|---4---|  (E) - 3rd
D|---|---|---5---|  (G) - 5th
A|---|---|---3---|  (C) - Root
E|---|---|---X---|  (Muted)

A Shape: Root on A string (5th fret), three fingers form A shape. Connects to G shape.

A Major - Open Position (0-2 frets)
e|---0---|---|---|  (E) - 5th
B|---2---|---|---|  (C#) - 3rd
G|---2---|---|---|  (A) - Root
D|---2---|---|---|  (E) - 5th
A|---0---|---|---|  (A) - Root
E|---X---|---|---|  (Muted)

A Shape at 5th fret (Root on A string)
e|---|---|---5---|  (A) - Root
B|---|---|---7---|  (E) - 5th
G|---|---|---6---|  (C#) - 3rd
D|---|---|---7---|  (A) - Root
A|---|---|---5---|  (A) - Root
E|---|---|---X---|  (Muted)

G Shape: Root on E string (3rd fret), four fingers form G shape (barre version). Connects to E shape.

G Major - Open Position (0-3 frets)
e|---3---|---|---|  (G) - Root
B|---0---|---|---|  (B) - 3rd
G|---0---|---|---|  (G) - Root
D|---0---|---|---|  (D) - 5th
A|---2---|---|---|  (B) - 3rd
E|---3---|---|---|  (G) - Root

G Shape at 3rd fret (Root on E string)
e|---|---|---3---|  (G) - Root
B|---|---|---4---|  (B) - 3rd
G|---|---|---4---|  (G) - Root
D|---|---|---5---|  (D) - 5th
A|---|---|---5---|  (B) - 3rd
E|---|---|---3---|  (G) - Root

E Shape: Root on E string (7th fret), barre across all six strings. Connects to D shape.

E Major - Open Position (0-2 frets)
e|---0---|---|---|  (E) - Root
B|---0---|---|---|  (B) - 3rd
G|---1---|---|---|  (G#) - 5th
D|---2---|---|---|  (E) - Root
A|---2---|---|---|  (B) - 3rd
E|---0---|---|---|  (E) - Root

E Shape at 7th fret (Root on E string) - Barre Chord
e|---|---|---|---|7|---|  (B) - 3rd
B|---|---|---|---|8|---|  (G#) - 5th
G|---|---|---|---|9|---|  (E) - Root
D|---|---|---|---|9|---|  (B) - 3rd
A|---|---|---|---|7|---|  (E) - Root
E|---|---|---|---|7|---|  (B) - 3rd

D Shape: Root on D string (5th fret), four fingers form D shape (partial barre). Connects to C shape.

D Major - Open Position (0-3 frets)
e|---2---|---|---|  (F#) - 3rd
B|---3---|---|---|  (D) - Root
G|---2---|---|---|  (A) - 5th
D|---0---|---|---|  (D) - Root
A|---X---|---|---|  (Muted)
E|---X---|---|---|  (Muted)

D Shape at 5th fret (Root on D string)
e|---|---|---|---|5|---|  (A) - 5th
B|---|---|---|---|7|---|  (D) - Root
G|---|---|---|---|7|---|  (F#) - 3rd
D|---|---|---|---|5|---|  (D) - Root
A|---|---|---|---X|---|  (Muted)
E|---|---|---|---X|---|  (Muted)

CAGED Connection Pattern:

C Shape (Root on A) → A Shape (Root on A) → G Shape (Root on E) → E Shape (Root on E) → D Shape (Root on D) → back to C

Example in C Major:
C Shape: 3rd fret (A string root)
A Shape: 3rd fret (A string root, different fingering)
G Shape: 8th fret (E string root)
E Shape: 8th fret (E string root, barre)
D Shape: 10th fret (D string root)

The Pentatonic Overlay ⭐⭐

Here is the part that turns shapes into solos: the minor pentatonic scale (1-♭3-4-5-♭7) nests inside each CAGED shape. Learn the pentatonic box that lives in the E shape and the A shape first — they cover the widest area and contain the classic blues positions.

Five boxes, five shapes: the pentatonic positions are usually taught as "boxes 1-5," but they are the same CAGED geometry with two notes per string removed. Box 1 sits inside the E shape, box 2 inside the D shape, box 3 inside the C shape, box 4 inside the A shape, box 5 inside the G shape.

Major vs minor: the same five notes, counted from a different root, give you the major pentatonic (1-2-3-5-6). The box around the C shape plays major pentatonic; slide the fingers one shape over and it's minor. Same dots, different centre of gravity.

Bending targets: in any box, the ♭3 of the scale bends up a whole step toward the 4, and the 4 bends toward the 5 — those two bends are 80% of blues phrasing. The root and the ♭7 are landing notes.

Bass players: the same logic transfers one string set down. The companion diagram for five-string bass lives on the music section front page.

Chord Tones and Extensions

The CAGED system visualizes chord tones (root, 3rd, 5th, 7th) across the fretboard. This facilitates:

• Chord voicings: Finding different inversions for variety.
• Arpeggios: Playing chord tones in sequence for solos.
• Extensions: Adding 9ths, 11ths, 13ths to basic triads.
• Scale patterns: Overlaying scales on chord shapes for improvisation.

Practical Application

Triad shapes: Each CAGED shape contains closed-position triads. Learn to play triads across three adjacent strings in each shape.

Major and minor shapes: The CAGED system applies to both major and minor chords. Minor shapes flatten the 3rd.

Connecting shapes: Each shape shares notes with the next. Practice transitioning between shapes along the string sets.

Continue the Series

• Part 1 — body shapes, pickups, and the amp chain: the hardware behind the sound you're mapping.
• Part 3 — studio and workbench: keep the instrument playable and capture what you practice.
• For ii-V-I voicings built from these shapes: Jazz Improvisation: Theory, Transcription & Practice Methods.