The submediant chord (vi in major, VI in minor) has two distinct roles. As a tonic substitute, it shares two common tones with I and can extend or prolong the tonic area. As a weaker predominant, it can move toward V. Its most tested use is the deceptive progression, where V resolves to vi instead of I, avoiding the expected authentic cadence and requiring careful voice leading: the leading tone still resolves up to scale degree 1, which becomes the third of vi.
- Tonic substitute: vi shares scale degrees 1 and 3 with I, so it can replace tonic without disrupting the harmonic logic of a phrase.
- Weak predominant: vi can move toward V, but it is a less common and less forceful predominant than IV or ii.
- Deceptive progression: V (or V7) moves to vi instead of I; the leading tone resolves up as expected, but the bass moves to scale degree 6 rather than 1.
- Deceptive cadence: A phrase-ending deceptive progression; the phrase feels interrupted rather than closed.
- VI in minor: In minor keys, VI is a major triad on scale degree 6; it functions similarly to vi in major as a tonic substitute or deceptive target.
In G major, write the voice leading for V7 moving to vi. Which voice carries the leading tone, and where does it go?
| Function of vi | Context | Typical progression |
|---|
| Tonic substitute | Extends tonic area | I - vi - IV or I - vi - ii |
| Weak predominant | Moves toward dominant | vi - V |
| Deceptive target | Follows dominant | V - vi (deceptive cadence) |