shell chord masterclass · 4 moveable shapes · root + 3 + 7

SHELL
voicings

Four moveable chord shapes that define every chord quality in music. The 3rd and 7th are the guide tones — they DEFINE the chord. Everything else is colour.
4 SHAPES · 12 KEYS · EVERY JAZZ TUNE

A shell voicing is just the essential bones of a chord: root + 3rd + 7th. The 5th isn't needed. The 9ths and 13ths are colour. The 3rd tells your ear "major or minor." The 7th tells your ear "rest or motion." Get these four shapes in your hands and you can play any jazz standard, any blues, any pop song.

The guide tones rule everything

The 3rd and 7th are called "guide tones" because they GUIDE your ear through chord changes. A maj7 has a major 3rd + a major 7th. A dom7 has a major 3rd + a flat 7th. A min7 has a flat 3rd + a flat 7th. A m7b5 has a flat 3rd + a flat 5 + flat 7th.

Master 4 shapes · Move to all 12 keys · Done

Because these shapes are moveable (no open strings), learning them in C means you have them in every key. Move the shape up 1 fret = C# version. Up 2 = D. Up 5 = F. The root tells you the chord name.

MAPThe Four Essential Chords

Cmaj7
R + 3 + 7
Major Seven
Resting chord. Stable, sweet. The "home" sound in major key tunes.
C7
R + 3 + b7
Dominant Seven
Tension chord. Wants to resolve. The "V" chord of any key. Blues uses this on every change.
Cm7
R + b3 + b7
Minor Seven
Reflective, calm. The "ii" chord in major keys. Foundation of fusion vamps.
Cm7b5
R + b3 + b5 + b7
Half-Diminished
Dark, unstable. The "ii" chord in minor keys. Sets up a minor ii-V resolution.
SHELL 01 · MAJOR SEVEN
Cmaj7
C — E — B · ROOT + Major 3 + Major 7
The "resting" chord — stable, lush, the major key home
M7

6th String Root · Fret 8

Cmaj7 — 6th STRING ROOT · R + 3 + maj7 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 e B G D A E R X 7 3
e|--x--- mute B|--x--- mute G|--9--- E (3) D|--9--- B (maj7) A|--x--- mute E|--8--- C (root)

5th String Root · Fret 3

Cmaj7 — 5th STRING ROOT · R + 3 + maj7 0 1 2 3 4 5 6 7 8 e B G D A E X R X 7 3
e|--x--- mute B|--5--- E (3) G|--4--- B (maj7) D|--x--- mute A|--3--- C (root) E|--x--- mute

How to move this shape

To play Dmaj7: slide the 6th-string-root shape UP 2 frets (root at fret 10). For Fmaj7: slide to fret 13, or use the 5th-string-root shape at fret 8. For Bbmaj7: 5th-string-root at fret 1. The fret of the root = the chord name.

Scale to play over Cmaj7

SCALE FOR Cmaj7 · C IONIAN · C D E F G A B · avoid F (4) as landing 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 e B G D A E R R R R R R R D D D D E E E E E E E F F F F G G G G G G A A A A A B B B B B B B
C — Root E — Maj 3 (chord tone) G — 5 B — Maj 7 (chord tone) D, A — 9, 13 (colours) F — 4 (AVOID landing!)

C Ionian (Major Scale) · C-D-E-F-G-A-B

The straight major scale. Target the chord tones (C, E, B) for "inside" lines. Use D and A (the 9 and 13) for colour. The F (the 4) is an AVOID note — it clashes hard with the E (the 3) below it. Use F as a passing note only, never a landing note.

Riffs over Cmaj7

RIFF 01 · CHORD-TONE ARPEGGIO

The Maj7 Sweep

e|--12-------------------|
B|-----12-13-------------|
G|---------12------------|
D|------------14-9-------|
A|---------------10------|
E|--------------------8--|
   B-C-E   B  E-D  C (root)
   maj7-R-3-maj7-3-9-R
Why it works Pure chord-tone outline. Lands on C (root), passes through B (maj7), E (3rd), back to root. Sounds "inside" — pure maj7 vocabulary.
RIFF 02 · MAJ7 → 6 RESOLUTION

The Lydian Lift

e|---------------------|
B|--13-12-10-8---------|
G|-------------9-------|
D|---------------------|
   D-B-A-G-A (high run
   resolving DOWN to A=13)
Why it works Starts on D (the 9, colourful), walks down through B (maj7), A (13), G (5), lands on A. The 13 is the SWEET maj7 colour note. Sounds Wes Montgomery.
SHELL 02 · DOMINANT SEVEN
C7
C — E — Bb · ROOT + Major 3 + Flat 7
The "tension" chord — wants to resolve. The blues lives here.
7

6th String Root · Fret 8

C7 — 6th STRING ROOT · R + 3 + b7 (DOMINANT) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 e B G D A E R X b7 3
e|--x--- mute B|--x--- mute G|--9--- E (3) D|--8--- Bb (b7) A|--x--- mute E|--8--- C (root)

5th String Root · Fret 3

C7 — 5th STRING ROOT · R + 3 + b7 (DOMINANT) 0 1 2 3 4 5 6 7 8 e B G D A E X R X b7 3
e|--x--- mute B|--5--- E (3) G|--3--- Bb (b7) D|--x--- mute A|--3--- C (root) E|--x--- mute

Maj7 → Dom7 · the single-note change

The only difference between Cmaj7 and C7 is the 7th. Lower it by one fret (B → Bb). Same root. Same 3rd. The b7 creates the tension that pulls toward another chord. One note transforms a "resting" chord into a "moving" chord.

Scale to play over C7

SCALE FOR C7 · C MIXOLYDIAN · C D E F G A Bb · the dominant scale 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 e B G D A E R R R R R R R D D D E E E E F F F G G G G A A A Bb Bb Bb Bb Bb Bb Bb Bb
C — Root E — Maj 3 (chord tone) G — 5 Bb — b7 (chord tone) D, A — 9, 13 (colours) F — passing only

C Mixolydian · C-D-E-F-G-A-Bb

Major scale with a flat 7. This is THE dominant chord scale — every blues, every funk groove, every V chord in jazz uses Mixolydian. Target C, E, Bb (the chord tones). The Bb is the magic — it's what makes the chord sound "bluesy" instead of "happy."

Riffs over C7

RIFF 01 · THE BLUES ESSENCE

3rd → b7 movement

e|---------------------|
B|---------------------|
G|--9-b(10)~~~9-8-7----|
D|---------------------|
   E (3) bend to F, release
   E (3), Eb (passing), D (9)
   This is THE blues sound
Why it works The bend from E (maj 3) to F creates that "Albert King" tension. The line then descends through chromatic territory back to the 9. Pure blues vocabulary over a dominant chord.
RIFF 02 · THE TARGET b7

Land on the Bb

e|----------------------|
B|--13-11-13-11---------|
G|-----------------12-10|
D|----------------------|
   D-C-D-C  then C-A
   walking down to land
   on Bb (B fret 11)
Why it works The b7 (Bb) is the defining note of the dom7 chord. Landing on it CONFIRMS to the listener that you're on C7, not Cmaj7. Jazz players target this note constantly.
SHELL 03 · MINOR SEVEN
Cm7
C — Eb — Bb · ROOT + Flat 3 + Flat 7
The "reflective" chord — calm, modal, the fusion vamp foundation
m7

6th String Root · Fret 8

Cm7 — 6th STRING ROOT · R + b3 + b7 (MINOR) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 e B G D A E R X b7 b3
e|--x--- mute B|--x--- mute G|--8--- Eb (b3) D|--8--- Bb (b7) A|--x--- mute E|--8--- C (root)

5th String Root · Fret 3

Cm7 — 5th STRING ROOT · R + b3 + b7 (MINOR) 0 1 2 3 4 5 6 7 8 e B G D A E X R X b7 b3
e|--x--- mute B|--4--- Eb (b3) G|--3--- Bb (b7) D|--x--- mute A|--3--- C (root) E|--x--- mute

C7 → Cm7 · the single-note change

Cm7 is C7 with the 3rd lowered. E → Eb. Same root. Same b7. That one note (lowering the 3rd) transforms the chord from "tense and bright" to "calm and reflective." The b3 is what creates the "minor" feeling.

Scale to play over Cm7

SCALE FOR Cm7 · C DORIAN · C D Eb F G A Bb · the bright minor with natural 6 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 e B G D A E R R R R R R R D D D Eb Eb Eb Eb Eb Eb Eb F F F G G G G G A A A A Bb Bb Bb Bb
C — Root Eb — b3 (chord tone) G — 5 Bb — b7 (chord tone) A — natural 6 (DORIAN colour!) D, F — 2, 4

C Dorian · C-D-Eb-F-G-A-Bb

Minor scale with a NATURAL 6 (A instead of Ab). The natural 6 is what makes Dorian sound "bright minor" instead of "sad minor." Use over any m7 chord that's NOT a tonic (so any minor chord that's NOT the home key). Same scale as your Bm Dorian work from before — just rooted on C.

Riffs over Cm7

RIFF 01 · THE DORIAN COLOUR

Land on the natural 6

e|---------------------|
B|---------10~~~~~-----|
G|-------8-------------|
D|--7-10---------------|
   A (target) on B fret 10
   = the NATURAL 6
   the Dorian sound
Why it works The natural 6 (A) is the DEFINING note of Dorian. Land on it with vibrato — it tells the listener you're playing Dorian, not Aeolian. Brighter, more hopeful sound.
RIFF 02 · CHORD-TONE TARGETING

R-b3-5-b7 outline

e|--------8-11---------|
B|----8-11-------------|
G|--8------------------|
D|---------------------|
   Eb-G-C-Eb  (b3-5-R-b3 octave)
   pure arpeggio
   stays inside the chord
Why it works Outlining the chord tones makes the harmony AUDIBLE. The listener can hear "yes, this is Cm7" because you're only playing notes IN the chord. Foundational jazz technique.
SHELL 04 · HALF-DIMINISHED
Cm7b5
C — Eb — Gb — Bb · ROOT + Flat 3 + Flat 5 + Flat 7
The "unstable" chord — dark, exotic, the ii of minor keys
ø

6th String Root · Fret 8

Cm7b5 — 6th STRING ROOT · R + b3 + b5 + b7 (HALF-DIMINISHED) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 e B G D A E R b5 b7 b3
e|--x--- mute B|--x--- mute G|--8--- Eb (b3) D|--8--- Bb (b7) A|--9--- Gb (b5) ★ KEY! E|--8--- C (root)

5th String Root · Fret 3

Cm7b5 — 5th STRING ROOT · R + b3 + b5 + b7 (HALF-DIMINISHED) 0 1 2 3 4 5 6 7 8 e B G D A E X R b5 b7 b3
e|--x--- mute B|--4--- Eb (b3) G|--3--- Bb (b7) D|--4--- Gb (b5) ★ KEY! A|--3--- C (root) E|--x--- mute

Cm7 → Cm7b5 · the b5 note

Cm7b5 is Cm7 with the 5th LOWERED. Normal m7 doesn't need the 5th (it's implied), but for m7b5 you MUST play the b5 — that's what distinguishes it from regular m7. The b5 is the "diminished" sound, the dark tension. Without it, the chord just sounds like regular Cm7.

Scale to play over Cm7b5

SCALE FOR Cm7b5 · C LOCRIAN · C Db Eb F Gb Ab Bb · the dark exotic 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 e B G D A E R R R R R R R Db Db Db Db Eb Eb Eb Eb F F F Gb Gb Gb Gb Gb Gb Ab Ab Ab Bb Bb Bb Bb
C — Root Eb — b3 (chord tone) Gb — b5 (KEY chord tone!) Bb — b7 (chord tone) Db, Ab — b2, b6 F — 4

C Locrian · C-Db-Eb-F-Gb-Ab-Bb

All the flats. The darkest scale. Used over m7b5 chords (and the iiø in minor ii-V-i progressions). The b5 (Gb) and b2 (Db) are the most distinctive notes. Land on the chord tones (C, Eb, Gb, Bb) — the b2 and b6 are passing colours.

Riffs over Cm7b5

RIFF 01 · THE b5 STATEMENT

Hit the b5 hard

e|---------------------|
B|--7~~~~~~~~~~~-------|
G|---------------------|
D|---------------------|
   Gb (b5) sustained
   with vibrato
   defines the chord
Why it works Sustaining the b5 makes the half-diminished sound INESCAPABLE. The listener hears the dark colour. Many jazz solos start a m7b5 statement by landing on the b5 — that's the signature move.
RIFF 02 · DESCENDING LOCRIAN

Walk down to root

e|---------------------|
B|--11-9-7-------------|
G|---------8-6---------|
D|---------------4-3---|
A|--------------------3|
   Bb-Ab-Gb-Eb-Db-F-Eb-C
   b7-b6-b5-b3-b2-4-b3-R
   pure Locrian descent
Why it works Descending lines feel like resolution. This walks through all the dark Locrian notes and LANDS on C (root) — releasing all the tension built up. The half-diminished sound followed by resolution = jazz vocabulary in one phrase.

PUT IT TOGETHERPractice Progressions

Use the 4 shapes in real progressions

Now that you have all 4 shapes, here are 3 essential progressions to drill them in context. Play through these slowly, using either the 6th-string-root or 5th-string-root versions of each chord.

1. The ii-V-I in C major

Dm7 → G7 → Cmaj7

The most common chord progression in jazz. Practice with 5th-string-root shapes (Dm7 fret 5, G7 fret 10, Cmaj7 fret 3) for minimum hand movement.

2. The ii-V-i in C minor

Dm7b5 → G7 → Cm7

The minor version. Notice the m7b5 is now in play — this is its natural home. Same V chord (G7), but resolves to minor.

3. The Jazz Blues turn-around

Cmaj7 → Am7 → Dm7 → G7 → Cmaj7

The "I-vi-ii-V-I" — used in 1000s of jazz standards (Autumn Leaves, All The Things You Are, Misty). Master this and you can sit in on jazz tunes.

PLANThe 5-Day Build

One chord per day · then put them together

DAY 1

Cmaj7 — both positions

15 minutes. Drill the 6th-string-root and 5th-string-root shapes. Then move the 6th-string-root shape to all 12 keys by sliding it up the neck (1 fret at a time). Say the chord name as you play it.

DAY 2

C7 — both positions

15 minutes. Same drill. Note how it differs from Cmaj7 by just ONE FRET on the 7th. That's the only change. Practice switching between Cmaj7 and C7 quickly — lower the 7th by 1 fret.

DAY 3

Cm7 — both positions + scale

20 minutes. Add the C Dorian scale practice. Play the chord, then improvise 4 bars of Dorian over it. Land on the natural 6 (A) to confirm Dorian.

DAY 4

Cm7b5 — both positions + scale

20 minutes. Hardest of the 4. Add the C Locrian scale. The b5 (Gb) MUST be played — without it, the chord just sounds like Cm7. Practice landing on Gb to confirm half-diminished.

DAY 5

Progressions · all 4 chords together

30 minutes. Practice the ii-V-I in C major (Dm7 → G7 → Cmaj7). Then minor ii-V-i (Dm7b5 → G7 → Cm7). Then the jazz blues turn-around. By end of session, you can play jazz changes.

ENDThe Big Picture

4 shapes · every chord in music

These four shells (maj7, dom7, m7, m7b5) cover every chord type you'll encounter in jazz, blues, fusion, pop, soul, R&B, and most modern music. Because they're moveable, you have them in all 12 keys instantly.

Guide tones are the secret — the 3 and 7 carry the harmony

Once your hands know these 4 shapes, you can sight-read a jazz lead sheet for the first time and PLAY THROUGH IT — because every chord symbol on the page is one of these 4 shapes (with optional colour added). That's the doorway into jazz.

Spend a month on these 4 shapes. Move them through all 12 keys. Practice the scales. Use the riffs. By end of month, you're a jazz player.