Take the one C-major grip you learned in movable triads — top three strings, frets 5 · 5 · 3 — and hold it. From this single shape, moving just one or two fingers gives you seven different chords: major, minor, sus4, augmented, diminished, maj7, and dominant 7. Same hand, one small nudge at a time.
Three strings, three jobs
The starting shape has one note per string, and each string does a fixed job:
- String 3 = the root. This names the chord, so we never move it. Slide it and you don't get a new chord quality — you change key.
- String 2 = the 3rd. This is the major / minor / sus4 switch.
- String 1 = the 5th. This is the dim / aug switch — and the slot where a 7th goes.
Learn those two switches and all seven chords fall out.
The seven formulas
Every quality is just the triad formula with one degree altered. Here they are as scale-degree recipes (♭ means lowered a half step):
| Chord | Formula | Notes (from C) | What changed from major |
|---|---|---|---|
| Major | 1 · 3 · 5 | C · E · G | — (the reference) |
| minor | 1 · ♭3 · 5 | C · E♭ · G | 3rd down a half step |
| sus4 | 1 · 4 · 5 | C · F · G | 3rd → 4th (up a half step) |
| aug | 1 · 3 · ♯5 | C · E · G♯ | 5th up a half step |
| dim | 1 · ♭3 · ♭5 | C · E♭ · G♭ | 3rd and 5th down |
| maj7 | 1 · 3 · 7 | C · E · B | 5th slot → major 7th (B) |
| 7 | 1 · 3 · ♭7 | C · E · B♭ | 5th slot → ♭7 (B♭) |
Switch A — string 2 sets the mood
Leave the root and fifth alone and just move the 3rd on string 2:
- Fret 4 → E♭, a minor 3rd → C minor (dark).
- Fret 5 → E, the major 3rd → C major (bright).
- Fret 6 → F, the 4th → Csus4 (no 3rd at all — neither bright nor dark, wants to resolve).
Switch B — string 1 sets the tension
Now leave string 2 and move the 5th on string 1:
- Fret 4 → G♯, a ♯5 → C augmented (floating, unstable).
- Fret 3 → G, the perfect 5th → the plain major.
- Fret 2 → G♭, a ♭5 → and if you also drop the 3rd, you get C diminished (tense).
Adding a 7th — the string-1 slot again
A 7th chord has four notes (1 · 3 · 5 · 7) but you only have three strings. So you keep the two notes that carry the chord's character — the root and the 3rd — and give up the least essential one, the 5th, using its string (string 1) for the 7th instead. Root + 3rd + 7th is enough to sound the whole colour:
- Fret 7 → B, a half step below the root → Cmaj7 (dreamy, sophisticated).
- Fret 6 → B♭, a whole step below the root → C7, the dominant 7 (bluesy, pulls forward).
Why drop the 5th and not the root or 3rd?
The 5th is the one chord tone that carries almost no identity — it just braces the chord. The root names it and the 3rd decides major vs. minor, so both have to stay. With only three strings, the 5th is the note you can spare, and its string becomes the home for the 7th. (On a full barre or open chord you have spare strings, so there you'd lower a doubled root to a 7th instead — same result, more room.)
It all moves
The best part: none of these are stuck on C. String 3 is the root, so slide the whole shape so that string 3 lands on fret 7 (D) and you have the same seven chords in D — D, Dm, Dsus4, Daug, Ddim, Dmaj7, D7. Seven grips × twelve keys = 84 chords under one hand.
Here is the map to memorise — the bold cell is what moves from plain major:
| Chord | String 3 (root) | String 2 (3rd) | String 1 (5th / 7th) |
|---|---|---|---|
| Major | 5 (C) | 5 (E) | 3 (G) |
| minor | 5 (C) | 4 (E♭) | 3 (G) |
| sus4 | 5 (C) | 6 (F) | 3 (G) |
| aug | 5 (C) | 5 (E) | 4 (G♯) |
| dim | 5 (C) | 4 (E♭) | 2 (G♭) |
| maj7 | 5 (C) | 5 (E) | 7 (B) |
| 7 | 5 (C) | 5 (E) | 6 (B♭) |
In one line: from one root-position grip, string 3 (root) stays put and names the chord, string 2 (the 3rd) flips major / minor / sus4, and string 1 (the 5th) switches dim / aug or becomes the 7th slot for maj7 and dominant 7 — seven chords from one shape.