“What A Wonderful World” is not only a beloved standard, but also a wonderful example of how modern music theory tricks can add support to simple harmonic progressions. It contains all the usual suspects of a pop tune (simple diatonic triads), and also includes several flavorful non-diatonic chords such as secondary dominants, borrowed chords, secondary leading tones, augmented chords, and inversions aplenty.
For a complete transcription of this song’s chords in the original key of F, you can download this PDF that I’ve arranged.
If you’re a guitarist, I’d recommend instead downloading this version in C instead, which uses a 5th fret capo and much easier chord shapes than the ones discussed here.
Intro and Verse Sections
The song is in the key of F, and begins on an F major chord. Knowing this, it’d be a good idea to quickly refresh our knowledge of the F scale and it’s diatonic triads.
Simple pop songs might include just a few of these chords, but this song will feature each them all. To begin, the song starts off with a loop between the I and ii chord – that’s F and Gm. However, beneath the Gm chord, the bass player continues to pluck away at F, meaning this Gm is better labeled as Gm/F, and might be thought of as an inverted Gm7. “Pedalling” on the bass this way tends to add softness to a chord progression, and it’s a technique we’ll see employed throughout the song. This intro chord progression only occurs once; we won’t ever hear it later on.
Next, we hear this song’s central progression, the verse section.
All of these chords are in the key of F, except for one. Don’t incriminate Bbmaj7 – that’s just the IV chord with an added “A” note. Instead, point your finger at A7 as the first chord to leave the key. We can recognize quickly that it’s out-of-key, because as we saw near the start, any “A” chords in this key are supposed to be of the minor variety: The iii chord in F is supposed to be Am, not A major. A7 is an A major triad with an added G and includes the note C#, which is not native to the key of F. This A7, that pulls our ear quite strongly to the ensuing Dm chord, is considered a “secondary dominant chord.” If we want to resolve strongly to a Dm chord, one of the best ways to do so is to preempt it with it’s dominant chord, A7. That’s why it’s getting the label V7/vi: It’s the V7 chord of the vi chord.
A Hidden Melody Appears…
If we ignore the chords altogether, and only focus on the notes that Louis sings, we’ll find a timeless melody comprises this verse section’s core. It’s commonly recognized as “Twinkle Twinkle Little Star,” a melody that was taken from Mozart who himself took it from earlier French folk songs. Hundreds of years later, the same melodic movement appears here under the disguise of new chords and 6/8 time.
Below we see this timeless melody arranged two ways: the second demonstrates the harmony we’d expect from this melody to create “Twinkle Twinkle Little Star” (or The Alphabet Song if that’s more your style), and only features the primary chords of the key of F which are the I, IV, and V (or F, Bb, and C). The first demonstrates the same exact melody but with the chords from “What A Wonderful World” underneath. In both instances the highest notes are identical, but the chords underneath are different, showcasing how a single melody might be reharmonized many different ways.
Chorus/Refrain
Once we strike that sad note of resolution to Dm, we’re quickly greeted with another non-diatonic chord. From Dm, we slip down a half-step to find another out-of-key note, Db, and from there a major chord is built. Then the chord progression concludes with a classic ii-V-I movement.
That Db chord is the centerpiece attraction in this song, and atop it, we hear the title of the song sung. Its presence is striking in the key of F, creating a solemn, magical, and surprising mood change away from the Dm chord we just encountered. This is often the effect that the bVI chord has in major keys, which is usually brought in under the title of a “borrowed chord.” While that title can mean many things, at the simplest level, borrowing a chord means writing in a major key but featuring a chord from the parallel minor key. In this instance, we’re in the key of F major, but suddenly seeing a chord that comes from the Fm key instead. The Fm key contains the following chords, all of which you should suspect to see pop up even when composing in F major because of their desirable sound.
Augmented Tonic Chord
Louis has just concluded singing the chorus, and we’ve resolved to our tonic chord of F, but instead of settling in there and getting comfortable, this song instead twists us away into uneasy dissonance with an augmented chord, which provides tension and excitement instead of peaceful satisfaction. Augmented chords don’t exist naturally in major keys, so any time you see one, it’s a sure sign we’re temporarily leaving the safety of our major scale.
In this instance, we see a classic use of the augmented triad, as the tonic chord itself (F major, which consists of F-A-C) sees it’s fifth note get raised a half-step to create the triad F-A-C#, called F+ (or Faug). That melodic movement from C to C# creates ascending momentum and can easily hint towards the note D; if we can follow up this F+ chord with any D-containing-chord, then we’ll probably have a nice sounding movement.
As discussed in chapters 10 and 16 of the Chord Progression Codex, there are many chords that fit that description; the one the composers chose here is the diatonic ii chord Gm, which does indeed require a D note for it’s fifth. That ii chord naturally leads to V, and then I again to begin repeating the verse and chorus. The chord is presented in inversion, with its third on the bass.
The Bridge
Once the verse and chorus have been repeated, we’re again treated with a short 4-chord-sequence that won’t be seen elsewhere. Instead of increasing the tension and dissonance, as shown before, this time we peacefully rock between our I and IV chords in preparation for the bridge section. Again, the bass player chooses to pedal on an F during this progression to create the following movement:
Then the bridge kicks off with history’s most famous progression, V – I. C to F appear side-by-side, firmly planting our ears into the key of F. Our tonic chord, F is played in second inversion to keep C on the bass, which allows this looping authentic cadence to feel less authoritative and more casual.
The jovial atmosphere gets darker as we now spend some quality time with Dm, the vi chord, and C, the V. Dm is the relative minor of F, and spending too much time here could reset our ear completely into believing we’re actually in the key of Dm. In fact, if we analyze just this progression in isolation, it’d best be described as Dm and not F. However, music is all about context, and here, we’re just temporarily wading into the home of our relative minor key, which adds a somber mood to our bridge.
The bass player, again, is quite bored with root-position-chords. Their choice of bass notes is reflected in the progression below:
Secondary Leading Tone Chord
After pedaling between Dm and C, the bridge ends with a ii – V – I. But before we get there, another special chord appears.
Let’s say we want to play a ii – V – I progression (Gm – C – F) , but we’d first like to approach the ii chord with style. One option is to first play it’s dominant chord, which as we discussed earlier is known as a secondary dominant. That would result in a progression like V7/ii – ii – V – I, or D7 – Gm – C – F.
Another option is to instead preempt the ii with its leading tone chord; that usually means the viiº7. The shortcut for accomplishing this is quite easy; to approach a chord, first descend a half-step and play a diminished 7th chord. In this instance, we want to approach Gm, so we go down a half-step to find F# and then play a dim7 chord there. As you can hear, this F#dim7 resolves decisively to Gm. In isolation, this movement is a viiº-i cadence, but here we see that it’s being used in a secondary fashion; to temporarily tonicize a diatonic chord. For that reason, we’ll label it as viiº/ii, the “seven of two.”
Secondary ii – V – i
For a final time, this song’s verse and chorus are repeated, and again we’re treated with a unique set of chords to conclude the chorus. This time, the chords emit a sense of finality, clearly telegraphing that a conclusion is nigh:
That D7 chord is another secondary dominant – it’s the V7/ii and will pull our ear strongly towards Gm, the ii chord in this song (and indeed, that’s the next chord in the sequence). This a classic jazz cliche, to introduce the V7/ii during a “turnaround” near the end of a song to let the listener know that the show is almost over – the chord has an iconic, ritzy, show-style vibe to it that’s hard to escape.
But what about that weird Aø/Eb chord (an A half diminished, aka Am7b5, that’s been inverted to have Eb on the bass)? Well, knowing that the next chord in the sequence is Gm, we can view this as part of a “minor 2 5 1 in G”. If we were in the key of Gm, then a ii – V – i would be the chords Aø – D7 – Gm. This three-chord movement is exceedingly popular and pleasant to the ears, and we’re using it here as a fancy way to arrive at Gm.
Here’s another way to think about that chord: If we wish to arrive at Gm with style, we first play it’s V7 chord (D7). If we wish to arrive at that D7 with style, we first play the iiº of Gm, which is Aø. This all works to target Gm, even though we’re in the key of F, and is usually called a secondary 2 5 1.
Altered Dominant Chord
After all of that work to finally get to Gm, we don’t actually get a full Gm chord. Instead, we get a defanged version of it: G7sus2. The resolution still works phenomenally well though – secondary movements aren’t required to resolve to bland triads! Then we see yet another ii – V7 – I in F, but this time, the V7 chord is altered. Altered dominant chords often show up in this context, as replacements for ordinary V7 chords. In this instance, we alter C7 by adding the note Db to create C7b9, a crunchy and dissonant chord that offers a touch of sorrow as we wave goodbye to Louis and this song.
Lastly, the song concludes with a peaceful plagal cadence between F and Bb, the I and IV, and a very memorable “oooh yeah!”
If you enjoyed this blog post, you’ll love my book The Chord Progression Codex. It teaches how chords work together to make modern-sounding music, like the song we’ve just explored here, and explains every bit of music theory you’ll need to know along the way.
