Introduction

In Lessons 7 and 8 we learned to write and analyze isolated triads. In this lesson we will explore how these chords relate to each other and function within a key.

1

Primary triads

The three most important chords are the primary triads. They are constructed above the first, fourth, and fifth pitches of the major or minor scale. In a diatonic major key, they are the three major triads and have a particularly close harmonic relationship. The dominant (V) lies a perfect fifth above the tonic, and the subdominant (IV) lies a perfect fifth below the tonic.

The tonic triad (I), constructed on the first scale degree, is first in importance. Tonal musical compositions often begin and almost invariably end on the tonic.

The dominant triad has strong harmonic influence. Because it contains the leading tone, it often precedes the tonic triad. The subdominant triad is the third most important chord. Following are the primary triads in the key of F major:

In a minor key, the harmonic form of the scale (raised 7th scale degree) is used. Therefore, the dominant triad is major. Following are the primary triads in the key of f minor: