Webeleon

Theory

Seventh-chord arpeggios from one shape

By Webeleon · 4 min read · Oct 12 2026

The seventh-chord arpeggios you meet in a ii–V–I — maj7, dominant 7, minor 7, half-diminished — are not four separate fingerings. They are one shape with up to three notes moved. Start with the Cmaj7 arpeggio on strings 6-5-4-3 (root on the low E string, eighth fret) and lower chord tones one at a time: the seventh for a dominant sound, the third for a minor sound, both for a plain minor 7, and add the fifth for the half-diminished chord that opens the minor ii–V–i. One small neighbourhood of the neck, four arpeggios, and the entire cadence in your hands.

The template

Here is the shape everything else derives from, on strings 6-5-4-3 with the root on the low E string:

  • Low E, fret 8: C (root)
  • A string, fret 7: E (third)
  • D string, fret 5: G (fifth)
  • G string, fret 4: B (seventh)

Cmaj7 — root, third, fifth, seventh, one string each, all fretted, fully moveable. Play it slowly up and down until the shape is just a shape. The derivation only works if the template is unconscious.

One note at a time

Now alter one chord tone at a time and name the chord that comes out. This is the whole article:

  • Lower the seventh, B to B♭ (G string, fret 3): C E G B♭. That is C7 — major third, minor seventh, the dominant sound in one move.
  • Restore the B, then lower the third, E to E♭ (A string, fret 6): C E♭ G B. That is Cm(maj7), the tonic chord of harmonic minor — minor triad with a major seventh, the sound that ends a minor-key cadence in the movies.
  • Lower the 3rd and the 7th together: C E♭ G B♭. That is Cm7, the plain minor-seventh chord and the ii of every major-key ii–V–I.
  • Lower the 3rd, the 5th (G to G♭, D string fret 4), and the 7th: C E♭ G♭ B♭. That is Cm7♭5, the half-diminished chord. The awkward name is just the receipt for three alterations you already understand.

No new shapes were memorised in that list. Each chord cost one fret of movement from the template, which is why this approach sticks: you are not learning four arpeggios, you are learning one arpeggio and three switches.

The payoff: a cadence in one position

String the results together in the order a cadence demands and the point makes itself. In C minor, the minor ii–V–i is Dm7♭5 (D F A♭ C), G7 (G B D F), Cm7 (C E♭ G B♭). Move the template to D and apply the triple lowering; move to G and lower only the seventh; return to C and lower the third and seventh. In C major, the same walk with fewer switches gives Dm7–

G7–Cmaj7. Three chords, one neighbourhood, your hand barely travels.

This is the difference between knowing arpeggios and being able to use them. A shape library gets you the notes; a derivation gets you the notes plus the relationships, and relationships are what let you improvise a line through a cadence instead of leaping between memorised boxes. When the changes go by at gig tempo, you do not have time to recall four shapes — you have time to recall one shape and which switches moved.

I worked this neighbourhood for a month before I trusted it on a bandstand, and it is still the first thing I check when my arpeggio lines feel stiff. Usually one of the switches has quietly reverted to the template.

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