Dragon Quest III “Heavenly Flight” Analysis 5: Tritone Substitution

Tritone Substitution and the Neapolitan Chord

This is part five of our practical music theory analysis of “Heavenly Flight” from Dragon Quest III.
Last time, we examined the bass line in the opening four bars.
This time, let’s focus on B♭7(9) and E7(9).

The Piece

Video Tutorial

1. Song Structure
2. Key and Tonality
3. Chord Progression
4. Focusing on the Bass Line
5. Tritone Substitution (This Article)
6. Bass-Line Cliché
7. Pedal Point
8. The Picardy Cadence

A Sound Close to the Neapolitan Chord

The chord in the second half of bar three, B♭7(9), is not diatonic to the A natural minor scale.

The usual diatonic chord on the second degree of A natural minor is Bm7♭5.
Lowering its root by a semitone gives a B♭-rooted sonority.
The resulting B♭–D–F triad is a major chord known in classical harmony as the Neapolitan chord.
The name comes from its use in seventeenth-century Neapolitan music.

The Neapolitan chord is conventionally a triad, as shown above,
and is usually placed in first inversion. The outer voices form a sixth, hence the name “Neapolitan sixth.”
Here, however, B♭7(9) is in root position and adds a minor seventh and ninth, making it a dominant seventh with a ninth. Lowering only the root of the full Bm7♭5 chord would leave A natural, so the dominant seventh A♭ is an additional alteration. Let’s continue the analysis.

Tritone Substitution

E7(9) in bar four functions as the dominant on the fifth degree of A minor; its dominant seventh chord is derived from harmonic minor.
Immediately before it comes another dominant seventh chord, B♭7(9). To examine their relationship,
look at the roots: they form an augmented fourth, equivalently a diminished fifth, also known as a tritone.

On the circle of fifths, notes a tritone apart sit opposite each other.
A dominant chord in this opposite position is commonly called a substitute dominant or tritone substitute.

The two chords share the notes forming the tritone,
which helps explain why both can have a dominant function.
For that reason, dominants can sometimes be substituted for one another or used in succession.

The Sound and Role of the Ninth

We have seen the progression move from the substitute dominant to the
primary dominant.
Both can also be understood as containing ninth tensions.

The ninth of B♭7(9), C, belongs to A minor and can be heard as reinforcing its tonality.
Furthermore, A♭ is enharmonically equivalent to G♯:
when considered against A harmonic minor, every chord tone except the B♭ root is in the scale.

The ninth of E7(9), F♯, belongs to A melodic minor and can also contribute a melodic, classical character to the harmony.

Frequently Asked Questions

Q1. What is a substitute dominant?

A substitute dominant can replace a dominant chord. Its root is a tritone away, opposite on the circle of fifths. The two dominant sevenths share the notes of their characteristic tritone, supporting a similar dominant function.

Q2. How is the Neapolitan chord related to this progression?

The B♭–D–F triad is the flat-II major triad in A minor, associated with the Neapolitan chord. The passage uses B♭7(9) in root position, with a minor seventh and ninth; it is related in sound but differs from the conventional first-inversion Neapolitan triad.

Q3. What role do ninths play here?

The ninth of B♭7(9), C, is in A minor and can reinforce its tonality. The ninth of E7(9), F♯, is found in A melodic minor and contributes to the melodic, classical character.