The notes of the G Major scale can be harmonized several ways. In this diagram each scale degree can function as the root, third, or fifth of a triad. The text below each note lists the chord where the note is the root, third, or fifth of the chord reading from left to right. For example note 5 (D) is the root of the V chord, the third of the iii chord, and the fifth of the I chord.
The I, IV, and V chords are the primary chords and are shown in bold type in the example above. In most folk, rock, pop, and blues songs the I, IV, and V chords account for over 90% of all chords used in the song. The most common ending in songs is the V-I chord progression.
In Example 2, every note of the G major scale is harmonized by a root position I, IV or V chord.
In Example 3, every note is harmonized by a I, IV, or V chord in various inversions.
The ii, iii, vi, and viiº chords are secondary chords used to provide additional harmonic color.
Example 4 uses both primary and secondary chords all in root position.
Example 5 uses the same primary and secondary chords all in various inversions.
Secondary chords that have two notes in common with a primary chord can be substituted for the primary chord.
Example 6 uses substitute chords in root position.
Example 7 uses substitute chords in various inversions.
Revised by John Ellinger, Spring 2012.