Lesson 5 — Second Inversion and the ⁶₄ Cadence

Second Inversion and Its Restrictions

When the fifth of the chord is in the bass, the chord is in second inversion (symbol: ⁶₄).

Second inversion is the most unstable of the three positions. For this reason, its use is very restricted in classical harmony. It has three accepted uses:

1. Cadential Use (the most important)

The I⁶₄ → V → I cadence is the most common and powerful use:

• The I⁶₄ appears over the dominant bass (G in C Major)
• The sixth (C) and fourth (E) resolve stepwise downward to the fifth (B) and third (G) of the dominant chord
• This is the moment of greatest tension before the final resolution

This pattern appears in virtually all tonal music: in the final cadence of a sonata, before the solo in a classical concerto (trill cadence), in opera arias. It is the "sigh" before the denouement.

2. Passing Use

The passing ⁶₄ chord appears on a weak beat between two root position chords whose roots are a third apart:

I → I⁶₄ (passing) → I⁶ (or vice versa)

3. Pedal (Neighbor) Use

The pedal ⁶₄ chord appears when the bass remains static (pedal point) and the upper voices temporarily form a ⁶₄:

I → I⁶₄ (neighbor) → I

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Second Inversion Doubling Rule

In second inversion, always double the fifth (which is the bass).

This rule has no exceptions in classical chorale.

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The Complete Chorale

In this lesson you integrate all the tools learned:

• Root position with root doubling
• First inversion with melodic bass line
• ⁶₄ → V → I cadence at the end

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Exercise

Write a complete chorale (6-10 chords) in one of the following keys: C Major, G Major, F Major, D Major, B♭ Major.

Requirement: The chorale must end with the sequence I⁶₄ → V → I.

This is the first time the exercise has no pre-set scheme — you decide the progression. Trust your musical judgment!