4 for IV, Part I: Secondary Plagal Progressions

Before beginning my analysis for this project, I didn’t really know much about The Go-Go’s. I knew they were an all female band from the 80’s that had some cheesy hits, but that was about the extent of it.


Knowledge and perspective can be funny things. I’m not ready to anoint them as successors to The Beatles or anything, but knowing what I do now, I certainly have a much greater respect for their musicianship.


As the introduction to this series discussed, the IV chord has a crucial role in rock/pop music harmonic progressions, particularly in relation to how the harmony is used in concert music. Songwriters have grown to love the chord so much that they have pioneered ways of using it that have given its function fresh vitality and have helped to further distinguish this genre from others.


Understanding Secondary Plagal Function


Perhaps the most common of these unique applications of the IV chord (and, specifically, its plagal function) is the use of secondary plagal progressions. A plagal progression results from a chord built on the fourth degree of the scale resolving directly to the tonic chord, with the root of the former being a perfect fourth above that of the latter. A secondary plagal progression, then, occurs when a chord whose root is a perfect fourth above the IV chord precedes it. This new chord will be built on lowered scale degree seven (bVII), which means it is not a diatonic chord. Its existence essentially extends plagal function to introduce a new harmony.


While there are very little if any examples of this harmony in classical/concert music,* there is a precedent for this kind of function in the form of secondary dominants. A secondary dominant chord is a non-diatonic harmony that functions as a dominant chord to a diatonic harmony. For example, in the key of C Major, the chord D Major does not exist. However, D Major would be the dominant harmony to G Major, which is the V chord in this key. The conventional way of notating D Major in the key of C would be “V/V” (read as “five-of-five”), with the chord to the left of the slash showing its dominant function, and the chord to the right showing its destination in the progression.


*The bVII chord – also known as subtonic – is found in this music, but it typically exists in the context of modal borrowing. Of course, I hardly have an exhaustive knowledge of classical repertoire, so I cannot claim with any conviction that it does not exist.


Probably the clearest and most well known example of secondary dominants can be found in the bridge of George Gershwin’s “I Got Rhythm” (a progression used so frequently it has become known as “rhythm changes”). The eight-measure bridge consists of four dominant seventh chords whose roots are all separated by descending perfect fifths. In the song’s usual key of Bb Major, the progression looks like this (vertical lines indicate barlines):


D7 |     | G7 |     | C7 |     | F7|     |


Of these chords, only the F7 (V7) is diatonic in the key of Bb Major. The other chords can be understood, however, as dominant chords that briefly shift the tonal emphasis to a diatonic harmony other than tonic. Therefore, the function of each chord would be the following:


D7 = V7/vi

G7 = V7/ii

C7 = V7/V

F7 = V7


Each secondary dominant moves to the root it is tonicizing, though except for the F7, that next chord is a different secondary dominant harmony instead of the expected diatonic harmony. In this light, this progression can be understood as a multi-layered web of secondary dominants rather than a succession of isolated chords. A notation that incorporates this perspective might look something like this:


D7 = V7/V/V/V

G7 = V7/V/V

C7 = V7/V

F7 = V7


Using this nomenclature, I refer to secondary plagal chords in this blog as IV/x rather than bVII, or whatever the altered root might be. Assuming the chord that follows is a descending fourth away, this will more accurately convey the function of the non-diatonic harmony.


Let’s look at some examples of this kind of chord in action, shall we?


The Kinks, “Celluloid Heroes”


For a straightforward example of how a secondary plagal progression works in practice, the chorus of The Kinks’ “Celluloid Heroes” works nicely. The verse, which is unusually long for a pop song, uses mostly diatonic harmonies in the song’s key of D Major, although it does contain an example of a secondary dominant. The following is the verse progression, which includes lead-sheet symbol notation for chords as well as their functional Roman numeral analysis parenthetically:


Verse: D (I) | A (V) | G (IV) | D (I) |

F#m (iii) | Bm (vi) | G (IV) | A (V) |

Bm (vi) | F#m (iii) | G (IV) | A (V) |

D7 (V7/IV) | G (IV) | A (V) | D (I) |


The chorus has only three chords, and they depict the most basic form of a secondary plagal progression. All three chords’ roots are separated by descending perfect fourths, with the final chord being tonic. Even though the progression starts with a non-diatonic chord, this is a fairly common progression in rock/pop music. The chorus begins at 1:33 in the recording, and it repeats four times.


Chorus: C (IV/IV) | G (IV) | D (I) |   |


As with secondary dominant harmony, the C Major chord in this progression is a chord not found in the key that briefly implies a different tonic (G Major here, the key’s IV chord) using the established sound of a plagal progression. Because it is achieved by means of a very comfortable sound, it does not come off as dissonant even though the chord isn’t in the key.


Bruce Springsteen, “Glory Days”


A popular rock anthem from the 80’s, “Glory Days” employs another common use of secondary plagal chords. Here, plagal progressions are used to embellish either tonic (I), subdominant (IV), or dominant (V) chords. Most measures contain three chords. The former and the latter are the same chord in a given measure, while the middle chord’s root is a perfect fourth above the root of the outer chord. There are essentially two levels of progressions working here: on a global level, there is a standard succession of tonic/predominant/dominant chords, but on a local level, there is a perpetual use of plagal progressions.


The following lays out the chord progressions for each section, as well as a formal diagram of the entire song. Once again, vertical lines in the progression represent barlines, but diagonal slashes between chords separate multiple chords used within a given measure. The key is A Major.


Intro: A (I) / D (IV) / A (I) | D (IV) / G (IV/IV) / D (IV) |


Verse: A (I) / D (IV) / A (I) | D (IV) / G (IV/IV) / D (IV) | (4x’s)

E (V) |   | D (IV) |   | E (V) |   | D (IV) | E (V) |


Chorus: A (I) / D (IV) / A (I) | D (IV) / G (IV/IV) / D (IV) | (2x’s)

A (I) / D (IV) / A (I) | E (V) | A (I) / D (IV) / A (I) | D (IV) / G (IV/IV) / D (IV) |


Bridge: E (V) / A (I) / E | E (V) / A (I) / E | D (IV) / G (IV/IV) / D (IV) | E |



Intro (4x’s): 0:00

V1: 0:16

Ch: 0:49

V2: 1:05

Ch: 1:39

Bridge: 1:55

V3: 2:03 (starts stripped down, subdominant embellishments are removed)

Ch: 2:36 (only 6 measures, which is repeated, then goes into vamp of Intro progression)


Of all the chords used, only G Major does not have diatonic function in the song’s key of A Major, and I analyzed this as a secondary plagal chord (IV/IV). However, an argument can be made that the A Major chord has secondary plagal function when it is used in the bridge. Even though this chord is tonic, it is used to embellish the E Major (V) chord during the bridge in the same way that D and G Major were used during the verse and chorus. So while it is the tonic chord, it doesn’t really have tonic function here. In this perspective, IV/V would be an alternative way of notating that harmony.


The D Major that appears in the first measure of the verse and chorus would not be a secondary plagal chord, by the way. While it does embellish the tonic chord, it already has plagal function as the key’s IV chord. It’s simply a plagal progression.


The Grateful Dead, “Touch of Grey”


Another song that demonstrates this embellishing approach is The Grateful Dead’s “Touch of Grey”. As with “Glory Days”, both the verse and chorus use a secondary plagal chord to embellish the song’s IV chord. Since the song is in B Major, that secondary plagal chord is A Major.


Intro: A (IV/IV) / E (IV) | A (IV/IV) / E (IV) | B (I) / F# (V) | B (I) / F# (V) |


Verse: B (I)| F# (V) / B (I) | E (IV) | A (IV/IV) / E (IV) | F# (V) | F# (V) / B (I) | E (IV) | E |


Chorus: F# (V) | B (I) | E (IV) | E | F# (V) | B (I) | E (IV) | E |

F# (V) | B (I) | A (IV/IV) / E (IV) | F# (V) |

E (IV) | A (IV/IV) / E (IV) | B (I) / F# (V) | B (I) / F# (V) | [intro progression at end]


Bridge: C#m (ii) | C# (V/V) | F# (V) | F# | C#m (ii) | C# (V/V) | F# (V) | F# |

G#m (vi) | D# (V/vi) | C# (V/V) | F# (V) | B7 (V/IV) | E (IV) | F# (V) | B (I) / F# (V) |



Intro: 0:00 (3x)

V1: 0:18 (2x)

Ch: 0:42

V2: 1:06 (2x)

Ch: 1:30

Bridge: 1:54

Guitar Solo (V): 2:18 (2x)

Guitar Solo (Ch): 2:42

Bridge: 3:06

V3: 3:31 (2x)

Ch: 3:55

V4: 4:18 (2x)

Ch: 4:42

Ch: 5:06

Ch: 5:31 (fade out)


Also similar to “Glory Days” is that “Touch of Grey” uses a diatonic chord that somewhat functions like secondary harmony. The chorus begins with a V – I – IV progression, which features three chords whose roots are separated by descending perfect fifths. This is similar to the progression seen in “Celluloid Heroes”, except the root movement is by fifth, and the destination is IV instead of I. However, at the very least it implies the IV chord as a tonic destination, which would make the I chord right before the IV a secondary dominant chord. The song also uses several chords that are unquestionably secondary dominants in its bridge, so its approach to secondary harmony is certainly notable.


Jimi Hendrix, “Hey Joe”


A good example of a song that extends this concept even further is Hendrix’ “Hey Joe”. Aside from its introduction, the entire song repeats the same progression. It is comprised of five different chords and spans four measures, with the first two each containing two chords and the final two with just one stretching across them:


C / G | D / A | E |   |


Analyzing this progression is somewhat complicated. The final E Major triad establishes the song’s tonic, but only the final two chords have a function in that key. One way to understand the first three chords is through modal borrowing. I alluded to this earlier, but modal borrowing results when harmonies found in a major key’s minor mode (or vice versa) are used in place of diatonic harmonies. In this instance, the C, G, and D Major chords can all be found in E minor rather than E Major. Through this perspective, the following provides a functional analysis of the progression:


bVI / bIII | bVII / IV | I |   |


Another way of accounting for this progression would be as a secondary plagal progression. Starting from the E Major chord and working backwards, each chord’s root is once again separated by a perfect fourth (ascending if you go backwards). An analysis that comprehends this perspective would look like this:


IV/IV/IV/IV / IV/IV/IV | IV/IV / IV | I |   |


This progression recalls that of the bridge from “I Got Rhythm” in that it is an extended chain of non-diatonic harmonies that imply other key areas. However, the notation required for notating this succession of secondary plagal chords is more cluttered because the chords that follow both the C and G Major chords are also not diatonic. This was not true in “I Got Rhythm”, which allowed for more concise symbols like V/vi. They could be written as IV/bIII and IV/bVII, but this doesn’t show their true function, and the fact that the chord to the right of the slash is not diatonic makes it less credible than the secondary dominant notation. Regardless, both progressions preemptively extend tonic through their use of cyclic root movement.


The Go-Go’s, “Our Lips are Sealed”


Which brings us back to The Go-Go’s. First of all, what little I thought I knew about the band before this blog seems to be mostly incorrect. They were a new wave punk band from the early 80’s, much more Blondie than Bananarama. They were the first (and currently only) all-female band to write and perform their own music to top the Billboard albums chart, and their debut album, Beauty and the Beast, is triple platinum, being generally adored by critics and the general public alike.


“Our Lips are Sealed” is probably one of their more recognizable hits, which makes sense. It’s a catchy pop song with a steady backbeat groove and a melody that sticks in your head. Take a closer look at its chord progression, though, and you’ll find something that is deceptively complex.


(Key of Ab Major)

Verse: Ab (I) | Gb (IV/IV) | Db (IV) | Db (IV)


Chorus: E (bVI) | Db (IV) | A (N) | Eb (V) | Ab (I) | Db (IV) | Ab (I) | Ab (I)




Intro (drums + guit + bass): 0:00

V1: 0:19 (2x)

Ch: 0:33 (1x)

V2: 0:49 (2x)

Ch: 1:03 (2x – last bar omitted before repeat)

Bridge: 1:31 (Vamp on Ab)

V3: 1:54 (2x)

Ch: 2:08 (2x – last bar omitted before repeat, vamp “Our lips are sealed”)


The verse features the only secondary plagal progression in the song, and as expected, the secondary plagal chord is followed by IV. This is a slight variation on the progression found in “Celluloid Heroes” in that it begins on tonic and then moves down a step to IV/IV. Because the progression repeats, it still ultimately moves towards tonic, but starting on tonic gives it a unique effect.


Although the chorus does not contain a secondary plagal chord, it has some very intriguing harmonies, and some that are at least tangentially related to the topic at hand. It begins on an E Major chord (or, enharmonically, Fb Major), which is another example of modal borrowing. However, there is an argument to be made that this chord is an abstract extension of the secondary plagal progression.


As seen in “Hey Joe”, extending backwards from tonic by perfect fourths will yield chords that would typically be found through modal borrowing. Even though the bVI chord* is a few layers removed from I and IV (it would be IV/IV/IV/IV), the fact that secondary plagal progressions are so strongly associated with rock/pop music means that this could be heard as an extension of the concept.


*I have found that the vi chord (or bVI) also tends to function like a plagal chord in rock/pop music on its own, but this would be a topic for another discussion.


A secondary harmony not moving directly to the chord it is tonicizing is not exactly unprecedented, either. This happens with secondary dominant chords, particularly in a progression that goes I -> V/V -> IV -> I (C Major -> D Major -> F Major -> C Major in the key of C, for example). The Beatles used this progression numerous times, and “Eight Days a Week” provides a very clear example of it. The progression works because it sounds good, and I think the reason it sounds good is because of the voice leading involved between the two chords.


Using the C Major example, the three chord tones of D Major are D, F#, and A, and for F Major they would be F, A, and C. When lining up the chord tones to create the smoothest voice leading, they move by either a whole step (D -> C), a half step (F# -> F) or not at all (A -> A). When these three differently sized movements are present between the voice leading for any two given chords, the resulting progression tends to have a good sound. This is true for V-I and IV-I progressions, for example, but really it works any time the roots of two chords are either a perfect fourth or minor third apart.


Because the E (Fb) -> Db progression from “Our Lips are Sealed” features root movement of a minor third, this same kind of voice leading occurs between these chords. As The Beatles did in “Eight Days a Week”, The Go-Go’s are essentially using a secondary harmony (plagal for The Go-Go’s, dominant for The Beatles) in a different context, but it was most likely an option at their disposal because of its original function.


The other non-diatonic chord used in the chorus is the A Major from the third measure. For the Roman numeral analysis, I labeled this chord as “N”. The astute reader will correctly point out that N does not have a value in Roman numerals; instead, it is an abbreviation for “Neapolitan”*, which refers to a major triad built on the lowered second scale degree. It is not an example of modal borrowing since this chord also does not exist in minor, but rather a substitute for a predominant chord. This is exactly how The Go-Go’s use it, as it is followed by the key’s V chord. Aside from rarely being used in rock/pop music, its presence here is noteworthy because of the root movement that precedes it. The roots of the first three chords of the chorus are E, Db (C# enharmonically), and A, which spell out an A Major triad. Arpeggiation is not uncommon in this music, but to so emphatically arpeggiate a chord that is a half step away from tonic is truly fascinating.


*This chord got its name through its strong association with the Neapolitan School of Italian opera composers. It is typically referred to as a Neapolitan sixth chord because it usually appears in first inversion.


The final noteworthy aspect of the chorus is the way it concludes. There is nothing unique about a I-IV-I progression, but this is the first time the diatonic plagal progression is used in the song, and the conclusion of the chorus is also the first time that two diatonic chords of any kind appear consecutively. After the craziness that came before it, this is an almost cheeky and overtly saccharine way of tying the whole progression together.


Perhaps The Go-Go’s just liked the sound of this progression, or perhaps this wry bit of sarcasm was their way of sticking it to pop conventions. Either way, it’s got me thinking.


Part 2 will discuss the IV chord and how it is used to create tonal ambiguity and introduce modulation, and I will be profiling songs by Green Day, Elton John, Counting Crows, Talking Heads, The Kinks (again), and They Might Be Giants.



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