Lesson 4 — First Inversion

The Sixth Chord

When the third of the chord is in the bass, we say the chord is in first inversion, represented by the symbol ⁶ (or "sixth chord" for the distance between the bass and the upper note).

For a C Major chord C-E-G:

• Root position: C in the bass → I
• First inversion: E in the bass → I⁶

---

What Is First Inversion Good For?

First inversion is less stable than root position — and that is precisely its usefulness:

1. Melodic bass line: Allows the bass to form a scale or a flowing line without changing chords
2. Avoid repetition: Alternates with root position to give variety to the bass
3. Smooth motion: The sixth chord "connects" two root positions with more elegance

---

First Inversion Doubling Rule

In first inversion, doubling is more flexible than in root position. The general rule:

In first inversion, the soprano or the highest available note can be doubled. Avoid doubling the third (which is the bass).

Exception: If the third is the leading tone (as in V⁶), it is sometimes doubled to avoid a bigger problem. Use judgment.

---

The ⁶₄ Cadence — First Look

In this lesson we introduce the concept of the cadential ⁶₄ (cadential second inversion). We'll cover it in detail in Lesson 5, but here we start preparing the ground.

The sequence I⁶₄ → V → I is the most powerful harmonic climax in classical chorale.

---

Exercise

Write progressions that include first inversion chords. End with a perfect authentic cadence (V → I in root position, soprano on the tonic).

Keys: C Major, G Major, F Major, D Major.