Take any note in the major scale. Stack the note a 3rd above it, then the note a 3rd above that. You get a triad. Do this on all seven degrees and you discover something remarkable: the sequence of chord qualities is always the same, regardless of key. This pattern is the foundation of all tonal harmony.
The Quality Pattern
Every major scale produces these seven triad qualities, in this order:
| Degree | Numeral | Quality |
|---|---|---|
| 1 | I | Major |
| 2 | ii | Minor |
| 3 | iii | Minor |
| 4 | IV | Major |
| 5 | V | Major |
| 6 | vi | Minor |
| 7 | vii° | Diminished |
Memorize the pattern: Maj min min Maj Maj min dim. In C major that gives you C, Dm, Em, F, G, Am, Bdim. In G major: G, Am, Bm, C, D, Em, F#dim. The roman numerals never change - only the letter names shift with the key.
Interactive Explorer
Select a key to see all seven diatonic triads. Each degree shows its chord tones on the fretboard and close voicing shapes on adjacent string groups.
I - C (C E G)
Major triad built on the 1st degree.
ii - Dm (D F A)
Minor triad built on the 2nd degree.
iii - Em (E G B)
Minor triad built on the 3rd degree.
IV - F (F A C)
Major triad built on the 4th degree.
V - G (G B D)
Major triad built on the 5th degree.
vi - Am (A C E)
Minor triad built on the 6th degree.
vii° - Bdim (B D F)
Diminished triad built on the 7th degree.
Practice
Ascending Walk
Play all seven triads ascending on one string group: I, ii, iii, IV, V, vi, vii°, I. Start in C major, 60 BPM, one chord per beat. Turn on the drone to hear the tonal center underneath. When that feels automatic, speed up to two chords per beat.
Quality Recognition
As you play each chord, say its quality out loud: "major, minor, minor, major, major, minor, diminished." This builds the association between the shape under your fingers and the sound coming out. Then switch to a new key and repeat - the roman numerals stay the same, only the starting position changes.
Why This Matters in Fourths Tuning
You need three shapes total: one for major triads, one for minor, one for diminished. Each shape works on every string group (E-A-D, A-D-G, D-G-C, G-C-F) with identical fingering. Three shapes, seven chords, every key. That is the P4 advantage applied to harmony.