Diatonic Chord Qualities

Learn why some chords in a key are major, some minor, and one diminished.

Instructions

1. Set Level 4, key of C Major on Guitar.
2. The Roman numeral row shows: I ii iii IV V vi vii°
3. Uppercase = major (I, IV, V). Lowercase = minor (ii, iii, vi). Circle = diminished (vii°).
4. Click each Roman numeral and watch the chord change: C, Dm, Em, F, G, Am, Bdim.
5. Notice: the quality (major/minor/dim) is built into the scale — it's not a choice, it's math.
6. Try the same in G major. The pattern is identical: I ii iii IV V vi vii°