Zion. T - Snow

Chord progression:

Am7 - D7sus4 D7 - Gmaj7 - E7sus4 E7

Am7 - D7sus4 D7 - Gmaj7 - E7sus4 E7

Am7 Bm7 - Cmaj7 D7(9) - Gmaj7 - Fmaj9 Fdim7

(Interlude:) Cm9 F13 - Bbm9 Eb6 - Am7 - D7

Right before interlude, he used Fmaj9 and Fdim7. I know that Fdim7 (Ddim7, Bdim7, or Abdim7) can resolve to half step up chords or a whole step below chords. But where did Fmaj9 came from? Where does that belong to?

My current thoughts are:

In the interlude, I think the key is changed from G to Bb to the Ab and back to G. So it is 2-5-1, not in BbM, but 2 in the key of Ab. So there is also 2-5.

Also, I discovered that Eb6 (Eb, G, C, Bb) and Am7(A, G, C, E) have same notes, G and C. And Eb and Bb is half step aeay from A and E.

3 Answers 3


Am7 - D7sus4 D7 - Gmaj7 - E7sus4 E7 x 2

Diatonic to a key signature of one sharp, G is a reasonable tonic. The E7 is a secondary dominant to the Am7, assuming x 2 means the progression repeats. Root progression by fifths.

Am7 Bm7 - Cmaj7 D7(9) - Gmaj7

Also a tonic of G. Note the root progression by steps, not fifths, I think that may be relevant to the "interlude."

For the next stuff, tonicize may be a better description than "change key."

Fmaj9 Fdim7 - (Interlude) Cm9...

...that tonicizes C, notice that Fdim7 could also be called Bdim7 which is often theoretically explained as an incomplete dominant seventh flat ninth chord, which would be a G7b9, the mode switches to minor, Cm, but that doesn't matter.

...F13 - Bbm9...

...tonicizes the Bb. In terms of keys it's "far" away from G major, but you could think of this as just a whole step down from Cm, sort of a sequential move.

If you accept the idea of Cm and Bbm as temporarily tonicized, notice that the change of tonics by step reflects the root progression by step in the earlier passage.


...that chord makes sense as a subdominant of Bb, but it also could be an inversion of Cm which would just shift us back up to tonic Cm. Either chord, Eb6 or Cm7 can be viewed as a "borrowed" chord in G major, which is a way to get things back to G.

Note that from root C in Cm9 to the Eb it's root progression by fifths. And if you regard the Fdim7 as an incomplete G7b9, then it's descending fifths G C F Bb Eb.

It's important to recognize those roots by descending fifths, because it's a very important harmony concept, and the progression of roots is more important than the details of the chord qualities major/minor/etc.

...Am7 - D7...

That seems to bring us back to tonic G

The part you labeled "interlude" seems like a "B" section of a song which is where you often find sequential harmony or diversions to other tonics. Because those moments are of short duration, they sound temporary, and so tonicize can be a better description that "key change."

You would need to show more detail, especially about melody and phrasing to say more re. tonicize versus key change.

...But where did Fmaj9 came from? Where does that belong to?

At least by my description, I'm saying it comes from the tonic C. It's the subdominant of C, and it was arrived at directly, there was no pivot chord, or that kind of thing. Moving from an initial tonic of G to C is perfectly ordinary.

If there is confusion about an F major chord in relation to a C minor tonic, and the changing between the tones A natural and A flat, understand that this would all be described as modal interchange or borrowed harmony. The critical idea is chord roots and tonal scale degrees are the principle elements of tonality whereas modal chord and scale degrees are only elements of modal coloring.

  • In case it is of interest, I’ve penned down the harmonic structure of the complete piece in my answer.
    – Lazy
    Jan 18 at 18:10
  • I was think more along the lines of a lead sheet where you can see melody and bar lines. Jan 18 at 18:38
  • Huh, you’re demanding ... Guess it’s somewhat like this petzel.at/sno.pdf
    – Lazy
    Jan 18 at 22:43
  • I'm not demanding anything of you @Lazy. I'm saying the chord list in your answer is not enough to make claims about phrasing which has bearing on key changes and such. Jan 18 at 23:30
  • It’s not like I meant that seriously...
    – Lazy
    Jan 18 at 23:40

So this is somewhat the harmonic structure of the piece:

Gmaj7(7) Cmaj7(3)
Gmaj7(7)/7 Cmaj7(3)
Bm7(3) em7(7)
Bm7(5-3) GP C/Em

Am7 D[4-3](9-8)
Gmaj7(7) E7[4-3]/7
Am7(7) D[5-8][4-3](5)
Gmaj7 E7[9-10]
Am7 D7
Gmaj7 E7[4-3][5-7]
Am7 Bm7 Cmaj7 D7
Gmaj7 → Fmaj7,9→Fo

Cm7,9 F7(6)
Bfm7,9 Ef7(6)
Am7,9 D7

Am7 D[4-3][9-8]
Gmaj7(7) E7[4-3]/7
Am7(7) D[5-8][4-3](5)
Gmaj7 E7[9-10]
Am7 D7
Gmaj7 E7[4-3][5-7]
Am7 Bm7 Cmaj7 D7
Gmaj7 E7

Am7 D7
G7 E7/[4-3]
Am7 D7


Am7 D7
Gmaj7 E7
Am7 Bm7 Cmaj7 D7

Gmaj7 E7
Am7 D7
Gmaj7 E7
Am7 Bm7 Cmaj7 D7

Gmaj7 E7
Am7 D7
Gmaj7 E7
Am7 Bm7 Cmaj7 D7

Gmaj7 E7

As you can see the piece is somewhat in G major, with a very prominent VI7-IIm cadence. Also as the Verse starts on the IIm this gives us a somewhat unclear tonic, with both G major and A minor taking a tonic like character.

The most prominent figure here is a short altered chain of fifths in the form II-V-I-VI7-(II).

Now, in the interlude we get Fmaj9→Fo, which does not stand on it’s own, but is superimposed on the previous Gmaj7.

This thus creates the harmonic effect of Gmaj7→G7,9,11,13→G7,b9 and thus an secundary dominant on the tonic. In fact this Fo can be seen as Bo, which simply makes it the classic diminished substitution for the Dominant G7 (in german we call this DV, a V7,b9 chord with omitted root, and one of the standard functions of a diminished 7th chord).

This secondary dominant then resolves correctly into the IV, but in minor. So we get a harmonic change to the IV but in minor, which is c minor. From there we get a modulating chain of 5ths (instead of a diatonic chain of fiths that would eventually lead us back to g minor). This means we get a sequence of pairs (dominant chord → non dominant chord), which forces the use of pure fifths and would eventually traverse the whole circle of fifths (it can be seen as a chain of V7→I=II→V7→I=II→..., so the Bf minor is simply a piece of the chain).

But this chain is cut short, and instead of going into Af we directly go back to A minor, leading us back to G major.

So instead of taking this as key changes I’d say it is a somewhat weird modulation of mode, from G major to G minor and back to G major. For a key change we’d need to have a change of tonic, but this section does not establish a true new tonic, the ear does expect a modulation back to either G (the tonic) or C (the subdominant). Just we’d rather expect to hear something like G7 | Cm7 F7 | Bfm7 Ef7 | Aø D7 | G, leading to the tonic, or G7 | Cm7 F7 | Bfm7 Ef7 | Afmaj7 Dø | G7 | Cm, leading back to the subdominant. Instead we get this unexpected Ef7 | Am7 D7.

EDIT: I’ve charted this out, for anyone who is interested, look here: http://petzel.at/sno.pdf

  • Given how common E7-Am7 and D7-Am7 are in the rest of the piece, I'd say only the introduction is in G major and the rest of the piece (except for the Cm7,9 F7(6) Bbm7,9 Eb7(6) passage) is in A minor. The piece ending with an E7 chord instead of a G or even D chord also supports the piece after the introduction and other than the Cm7,9 F7(6) Bbm7,9 Eb7(6) passage being in A minor, as E7 is V7 in A minor (and ending the piece on the dominant is one of the most common unresolved endings, in my experience).
    – Dekkadeci
    Jan 18 at 13:34
  • @Dekkadeci As I stated the tonic is very unclear, as we get two very prominent cadences. E7-Am is not really more common than D7-G, rather we get some sort of cycle Am-D7-G-E7-Am-D7-G-.... In fact if we factor out the dominants the basic chord structure we get is Am-G repeated. Switching between two neighboring steps seems to be a very common thing in modern pop music. Still I’d put this as G major, as the final cadence of each structural section is a D7-G. The full base cadence for this seems to be I-VI7-II-V7-I, as clearly stated in the end.
    – Lazy
    Jan 18 at 13:47
  • No, the final cadence of each structural section is not D7-G. Taking every single double line break as a section break, we get C/Em, then D7-Gmaj7 → Fmaj7,9→Fo, then Eb7(6)-Am7,9-D7, then D7-Gmaj7-D7, then E7/[4-3]-Am7-D7, then Cmaj7-D7 three times in a row, and finally Gmaj7-E7. (Taking only labels such as Verse II as section indicators gets silly quickly due to there being only 3 such labels and the majority of the chords being after the last label.) Even with a different section indicator system that ignores more double line breaks, E7/[4-3]-Am7-D7 still isn't a D7-G cadence.
    – Dekkadeci
    Jan 18 at 14:06
  • While the Am7-D7-Gmaj7-E7 cycle exists, the simplest interpretation of it involves as few secondary dominants and tonicizations as possible. Keeping the entire cycle in A minor pulls that off while still remaining reasonably within common practice period harmony, while keeping the entire cycle in G major fails to explain the E7 chords, and assigning E7-Am7 to A minor and D7-Gmaj7 to G major involves too many tonicizations(/modulations).
    – Dekkadeci
    Jan 18 at 14:10
  • 1
    @Dekkadeci I must ask, have you ever listened to the piece? It seems like you want to make a point just by looking at a few chord changes. I have listened to the piece quite a bit to chart it out petzel.at/sno.pdf so I am quite sure which cadenzas feel like tonic resolutions and which do not.
    – Lazy
    Jan 19 at 12:03

Assuming all the chord progressions you provided are correct, and without listening to the piece...

The chord progression Am7 - D7sus4 D7 - Gmaj7 - E7sus4 E7 x 2 Am7 Bm7 - Cmaj7 D7(9) - Gmaj7 - Fmaj9 is actually in A minor, not G major. The E -> Am general chord progression at the E7 x 2 Am7 section and the fact that the chord progression starts with Am7 are both strong giveaways that the chord progression is in A minor. The D7 - Gmaj7 and D7(9) - Gmaj7, regardless of their resemblance to a V-I chord progression in G major, can be interpreted as a mere IV7-VII7 in A minor.

The Fmaj9 chord at the end can therefore be interpreted as VI9 in A minor, since A minor includes both F natural and F♯.

The Cm9 F13 - Bbm9 Eb6 - Am7 - D7 section is trickier to interpret, but assuming there is a key change from C minor to B flat minor in the first 4 chords (and strong parallelism) is a more solid interpretation than assuming all 4 chords are in B flat minor due to F13 containing D natural. The Am7 - D7 wrenches us back into A minor due to a similar chord progression being used at the very beginning of the piece.

The key change from C minor to B flat minor is facilitated by Cm9 F13 - Bbm9 sounding a lot like a ii-V-i chord progression in B flat minor. Bbm9 Eb6 similarly sounds like ii-V in A flat major...but the chord progression never reaches an Ab chord, so I hesitate to say the piece ever goes to A flat major. Note that Cm9 F13 - Bbm9 Eb6 can be interpreted as Cm: i9 -> IV13 = Bbm: V♮13 -> i9 -> IV"6" (note that IV6 actually stands for IV in first inversion).

You are right that Eb6 (Eb, G, C, Bb) and Am7(A, G, C, E) share G and C, and Eb and Bb are a half step away from A and E, so the voice leading between Eb6 and Am7 is shockingly smooth and eases that otherwise (more) jarring transition.

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