IV. Diatonic Harmony, Tonicization, and Modulation

# Tonicization

John Peterson and Megan Lavengood

Key Takeaways

• Tonicization is the process of making a non-tonic chord sound like a temporary tonic. This is done with chromatic chords called applied chords, or secondary dominant chords (V(7)) and secondary leading-tone chords (viio(7)borrowed from the temporary key.
• Another way of thinking about applied chords is to imagine them as altered versions of the diatonic chord with which it shares a root (for example, ii becomes II♯, which is V/V).
• Applied chords are notated with a slash. The chord before the slash is the identity of the applied chord within the , and the chord after the slash is the chord being tonicized. It’s read aloud left-to-right with the word “of” replacing the slash: V/ii becomes “five of two.”
• Applied chords nearly always involve , and especially accidentals that raise the pitch.

When you come across a chromatic note, stop and ask the following questions:

1. Is the chromatic note part of the chord or is it an embellishing tone?
1. Part of the chord: move on to question 2
2. Embellishing tone: label appropriately
2. What’s the quality of the chord?
1. Major triad or dominant seventh chord: secondary V chord; label is V(7)/x
2. Diminished triad or diminished seventh: secondary viio chord; label is viio(7)/x
3. To determine x above, ask: in what key is the chromatic chord V or viio? Then, determine what Roman numeral the tonic triad of that key would get in the home key of your passage. The Roman numeral is x.

To spell an applied chord:

1. Determine the root of the chord being tonicized
2. Pretend that root is the tonic of a temporary key
3. Spell the top Roman numeral in that key (either V(7) or viio(7))

is the process of making a non-tonic chord temporarily sound like tonic. It’s accomplished using or chords (sometimes called applied dominant and applied leading-tone chords). First, we’ll learn how to tonicize the dominant, and then we’ll see tonicizations of non-dominant chords.

# Tonicizing V

## Analyzing tonicization

### Secondary dominant chords (V(7)/V)

Example 1 analyzes a passage that temporarily makes V sound like the tonic chord. Example 2 extracts the two chords from Example 1 that participate in the tonicization. If we were to analyze these chords without considering the key signature or the context that Example 1 provides, we’d say the two chords represent the progression $\mathrm{V^6_5}$–I in F major (Example 2a). That is, we have a C7 chord moving to an F major triad.

Example 1. Tonicization in Joseph Bologne, Six Concertante Quartets, No. 1, II, mm. 1–8.

Example 2. Reduction of the tonicization in Joseph Bologne, Six Concertante Quartets No. 1, II, mm. 3–4.

If we now reconsider the context that Example 1 provides, we can see that the F major chord functions as V in the excerpt’s home key of B♭ major (Example 2b). Indeed, it’s the chord that creates the half cadence that ends the first phrase. We know that we haven’t changed keys here because, in addition to the half cadence being in B♭ major, the second phrase also begins in B♭ major (it repeats the beginning of the first phrase). The C7 chord, however, clearly doesn’t belong to B♭ major. That’s what the E♮ accidental in the bass tells us. As we determined in Example 2, the C7 chord is $\mathrm{V^6_5}$ of the F major chord. To represent that in the context of Example 1, we say that the C7 chord is “$\mathrm{V^6_5}$ of V,” And we write “$\mathrm{V^6_5/V}$.” In other words, the F major chord is V, and the C7 chord is the $\mathrm{V^6_5}$ of that V chord. We’ve just labeled our first secondary dominant chord!

Tonicization can also be accomplished using secondary leading-tone chords, as in Example 3.

Example 3. Tonicization in Josephine Lang, “Du gleichst dem klaren blanen See,” mm. 21–24.

Example 4. Reduction of the tonicization in Josephine Lang.

Example 4 walks through how to understand the relationship between the two highlighted chords in Example 3.

1. If we were in G major, we would analyze these chords as viio7–I. Recall that when we learned about the leading-tone 7th chord, we discovered that it’s common to lower the chordal 7th in major to create a fully-diminished 7th chord. That’s still true here (notice the E♭!)
2. The passage in Example 3 is in C major, so we would analyze the G major chord as V, rather than I. That means the F♯o7 chord is viio7 of the V chord. We write “viio7/V” and say “seven diminished seven of five.”
3. The passage in Example 3 adds a $\mathrm{cad.^6_4}$ to embellish the dominant. That’s why the viio7/V doesn’t resolve directly to V.
4. The $\mathrm{cad.^6_4}$ resolves to V7 rather than the V triad. Now we’ve arrived at the passage in Example 3.

### Summary: Steps for analyzing tonicization

Note: It’s rare but possible in classical music to have a half-diminished seventh chord act as an applied chord. It’s even less common in jazz, where it’s almost certainly an applied iiø7.

Chromaticism is an indication that tonicization may be present. Since only V(7) and viio7 (or, rarely, viiø7—see note in sidebar) can create tonicization, one of the most helpful things to determine the label is to ask “what is the quality of the chromatic chord?” The quality determines the label: if the chord is a major triad or dominant seventh, it gets the label V(7). If the chord is a diminished triad or diminished seventh, it gets the label viio(7).

When you come across a chromatic note, stop and ask the following questions:

1. Is the chromatic note part of the chord or is it an embellishing tone?
1. Part of the chord: move on to question 2
2. Embellishing tone: label appropriately
2. What’s the quality of the chord?
1. Major triad or dominant seventh chord: secondary V chord; label is V(7)/x
2. Diminished triad or diminished seventh: secondary viio chord; label is viio7/x
3. To determine x above, ask: in what key is the chromatic chord V or viio? Then, determine what Roman numeral the tonic triad of that key would get in the home key of your passage. The Roman numeral is x.

## Writing applied chords

### Spelling

The video in Example 5 walks through the steps for spelling V7/V, viio7/V, and viiø7/V in major and minor keys. We recommend you grab a piece of staff paper so you can follow along by pausing the video and trying the exercises yourself. The steps are summarized below:

1. Determine the root of the chord being tonicized
2. Pretend that root is the tonic of a temporary key
3. Spell the top Roman numeral in that key (either V7, viio7)

Example 5. Steps for spelling applied chords.

### Resolving

The leading tone of the applied chord is referred to as the secondary leading tone; the seventh as the secondary seventh. These dissonances resolve just as they normally would in their own key.

One exception is that when the tonicized chord is itself a seventh chord—as in the progression D7–G7–C—the secondary leading tone may resolve down by semitone into the seventh of the following chord. In the example progression, this would create a nice chromatic line: F♯—F♮—E (Example 6).

The video in Example 7 walks through the steps for spelling V7/V, viio7/V, and viiø7/V in major and minor keys. We recommend you grab a piece of staff paper so you can follow along by pausing the video and trying the exercises yourself. The steps are summarized below:

1. Spell the secondary chord
2. Follow the to part write, but think in the temporary new key to determine how tendency tones resolve.
3. Check accidentals (especially if in minor)

Example 7. Steps for resolving applied chords.

# Tonicizing Chords Other Than V

## Overview

Any major or minor triad (not just V!) can be tonicized (except diminished and augmented triads, which makes sense when you think about all of the keys that we know—there are no diminished or augmented keys, which means that no diminished or augmented triad is the tonic of a key. That means that every Roman numeral can be tonicized except viio and iio).

## Analyzing Various Tonicizations

The steps for analyzing tonicization that we learned earlier when we were tonicizing only V remain the same here. The only difference is that we can now expect to find chords other than V being tonicized. Be on the lookout for chromatic notes: these are signals that tonicization may be present!

As you might imagine, the frequency with which a given chord is tonicized is related to the frequency with which that chord generally appears. For instance, the dominant and strong pre-dominant chords are quite common, so we also see those chords tonicized with some frequency. The vi chord, while less common than ii, IV, and V, also frequently gets tonicized. The iii and VII (minor only) chords are uncommon harmonies, and we tend not to see them tonicized frequently.

### Tonicizing Strong Pre-Dominants

Tonicizing strong pre-dominants usually involves chromatic inflection of members of the tonic triad. For example, a tonic triad can easily be turned into a V7/IV chord by adding te $(\downarrow\hat7)$ to the triad (Example 8). Similarly, a tonic triad can be turned into viio7/ii by raising do ($\hat{1}$) and adding te $(\downarrow\hat7)$  (Example 9).

Example 8. Tonicizing IV in Joseph Bologne, String Quartet No. 4, I, mm. 41–47 (1:18–1:30).

Example 9. Tonicizing ii in Maria Szymanowska, Minuet No. 4, mm. 57–64 (1:48–1:55).

# Tonicized Deceptive Motion

One striking way to use tonicization is to highlight a deceptive motion (Example 10). Here, the dominant moves to viio7/vi before the vi chord arrives, which draws our attention even more to the absence of the expected tonic after the V chord.

Example 10. Tonicized deceptive motion in Josephine Lang, “Mag da draussen Sehnee,” mm. 1–5.

# Adding Tonicization to Diatonic Progressions

The steps for part writing tonicization remain the same as when we part wrote tonicizations of V. Now, however, we should expect to see tonicizations of non-dominant major and minor triads. Example 11 shows a diatonic progression (a) to which several tonicizations have been added (b).

Example 11. Adding tonicizations to a diatonic progression.

# Secondary dominants as altered diatonic chords

Another way of thinking about secondary chords is to imagine them as altered versions of the diatonic chord with which it shares a root.

The most straightforward example is when a ii chord is chromatically altered by changing fa ($\hat{4}$) to Fi ($\uparrow\hat{4}$), and then progresses, like usual, to the dominant chord. This alteration of fa to fi $(\hat4-\uparrow\hat4)$ turns a regular into a chord that has a dominant function in the key of the dominant.

Take the chord progression Dm7–G–C in C major. We would label this progression as ii7–V–I with Roman numerals. If we change fa to fi $(\hat4-\uparrow\hat4)$, F–F♯), we get D7–G–C. In the key of C, we might analyze this progression as II♯7–V–I, noting the change in root and quality. However, we can also note that D major belongs to G major; it is a dominant-functioning chord (V) in the key of G—the key in which the following chord is tonic. In other words, we are borrowing the dominant chord from the key of G and applying it to the G-major triad. Thus, we can re-interpret the progression as V7/V–V–I.

Practice it!

Add accidentals in the following chords to turn them into secondary dominants. What Roman numeral would you give the new chord?

Example 12 summarizes secondary chords as they relate to diatonic chords with the same root.

Assignments
1. Applied chords worksheet A (.pdf, .mscx). Asks students to identify and write applied V, V7, viio, viio7, and viiø7 chords.
2. Applied chords worksheet B without ø7s (.pdf, .mscz). Asks students to identify and write applied V, V7, viio, and viio7 chords.
3. All applied chords (.pdf, .docx). Asks students to write from Roman numerals and figured bass, a longer figured bass, and analyze a complete piece with discussion questions.