The Neapolitan Chord (♭II)

The borrowed chords of the previous lesson all came from the parallel key. ♭VI, ♭III, and ♭VII are minor-key diatonic chords imported into major as they stand.

The chord in this lesson is different. The major triad on ♭II is not diatonic to either major or minor. Neither C major nor C minor contains a Db major triad. It is nonetheless standard in classical harmony and has a name of its own: the Neapolitan chord.

The major triad on ♭II

Construction is simple. Take the note a minor 2nd above the tonic as the root and build a major triad.

In both C major and C minor the tonic is C, so the root is Db and the notes are Db F Ab. Note that the chord is identical in both modes: parallel keys share their second degree, so the position a half step below it is shared too.

And there is an important convention: the Neapolitan is used in first inversion. That is the standard form, and the 6 in the conventional label N6 is that inversion figure.

Why first inversion? Look at the bass.

Position	Bass	Degree of the bass
Root position	Db	♭2 (outside the key)
First inversion	F	4 (subdominant)
Second inversion	Ab	♭6 (outside the key)

The bass of first inversion is the subdominant. In C, iv (F Ab C) and the first inversion of ii both put F in the bass as well. Since the ear uses the bass as its cue for a chord’s role, anything built over F is received as belonging to the subdominant family.

So the Neapolitan is a heavily colored subdominant. Root position would bring the out-of-key ♭2 into the most prominent position and obscure the function.

Check

What note is in the bass of the Neapolitan (N6) in A minor?

FABbD

Check answer

Two notations — N6 and ♭II6

The same chord is written two ways.

• N6 — the conventional dedicated symbol, read “Neapolitan sixth”
• ♭II6 — derived mechanically from degree and quality

Neither is wrong. N6 carries the claim that this chord has a special role; ♭II6 takes the position that it is merely the first inversion of a major triad on ♭II. This site’s Roman numeral tool outputs the systematic ♭II6, while the lessons give the conventional N6 alongside it.

One chord having two names is a case of different notations revealing different things — the same situation as I64 and figured bass in Unit 3.

Resolution — to the dominant, avoiding a diminished 3rd

The Neapolitan goes to the dominant. Being a subdominant, it proceeds to dominant function directly.

One problem arises. The root of N6 is Db and the leading tone of the dominant is B, and the distance between them is a diminished 3rd — an interval awkward to sing and avoided in classical harmony.

The standard remedy is to insert the second-inversion tonic chord (i64) between them.

In Fig. 2 the soprano moves directly from Db to B, a descending diminished 3rd. The shape does occur in real repertoire, but for a smoother line the following is preferred.

Two routes from N6 to the dominant

▶N6 → V (direct)▶N6 → i64 → V

Check: Both go from N6 through V to the tonic in C minor. In the first, Db drops straight to the leading tone B, putting a kink in the upper voice. In the second the line passes through the tonic C, giving Db → C → B in half steps. Listen for the diminished 3rd leap being decomposed into two stepwise motions.

Db falls a diminished 3rd to B

N6 can also proceed to the dominant seventh. In V7 the seventh, F, is the same note as the bass of N6, so the bass can be held while only the upper voices move, and the diminished 3rd problem is less likely to arise.

It works in major too

The Neapolitan is most often encountered in minor, but it is available in major in the same form, with the same notes, Db F Ab.

In major the chord introduces more alteration — Db and Ab both depart from the scale’s D and A — so its effect is stronger than in minor. In minor, Ab is already diatonic, and only Db is new.

Check

Using N6 in C minor, how many of its notes lie outside the C natural minor scale?

onetwothreenone

Check answer

▶ Check the Db major triad in the chord finder Entering Db as a chord name displays the notes Db F Ab. Playing it against the C minor tonic chord Cm (C Eb G) shows how distant a root a half step away can feel Chord Finder →

The crux of the Neapolitan is the Db placed a half step above the tonic. That note wants to descend a half step to the tonic C, and it passes through the dominant on the way. Remember it as a chord that approaches the tonic from above.

The next lesson covers chords that close in on the dominant by half step from above and below simultaneously: the augmented sixth chords.