I'm analysing this Jazz Standard. And it's quite straightforward with some major and minor II-V cadences here and there yet there is a chord I don't know how to explain, and it is that Db7 indicated red square (bar 10 not counting the pickup bar) on the score below:

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So, the thing is, how do I -harmonically speaking-, explain/justify this chord?

  • 1
    I like to feel it as a substitute for the IVm chord. On the guitar it feels especially natural to substitute Abm6 with Db9.
    – Pedro
    Dec 26, 2020 at 18:55

2 Answers 2



You can see it as somewhat similar to what a Bb/D chord would do in the same spot, but as an added twist temporarily switching to a scale which has Eb - F - G - Ab - Bb - Cb - Db. So the Db7 is a "♭VII7" chord. Some people call bVII - I a "backdoor" progression. See the Wikipedia page. bVII is called a backdoor, as opposed to the more usual V, which would be the "front door". I don't know if those names make it any easier to understand. To me it's just a bVII and extra names don't add any new level of understanding, but YMMV.

Try soloing with the scale Eb - F - G - Ab - Bb - Cb - Db over that chord. I guess this scale should be called "Eb Mixolydian b6". If it was a regular Db chord instead of Db7, you could use plain Eb Mixolydian as well. But the Cb note being in the Db7 chord kind of forces C to be flat there. (Which could be a matter of taste though)

This has been asked many times. Here's a recent question about the same thing: Why does C9 sound so good resolving to D major 7

Here's an example of using bVII7 instead of V in a simple song.

Mary Had a Little Lamb

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    I would guess that the links in your answer cover this, but it's worth noting that regarding naming, the change is called "backdoor" because the "front door" is the regular ii-V of Eb, and the "back door" is the ii-V of Gb (Gb is the relative major of Eb's parallel minor). In Eb, you'll often find Abm7 Db7 Ebmaj7, and here both the Abm7 and Db7 point towards Gb/Ebm, but instead enter Eb major "through the backdoor". The term sometimes gets used without the preceding m7 chord as bVII - I.
    – user45266
    Dec 26, 2020 at 8:44
  • If you solo over Db chord, the scale is Db-something. In this case, Db mixolydian #4, the fourth mode of melodic minor Oct 23, 2023 at 1:24

I continue to campaign for ♭VII - so frequently encountered in jazz-tinged popular music - to be awarded Honorary Diatonic Status. Then we can put this frequent query to bed once and for all!

Or, perhaps, if we wish to conserve the purity of 'diatonic', accept that 'borrowed chords' from the parallel minor are so commonplace as to be unremarkable.

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    It seems no less diatonic that any of the Augmented Sixth or Neapolitan or common-tone diminished chords which do not usually lead to a key change. There seems to be more than one way to use the chord. One is as IV/IV where bVII to IV to ... can be used or just bVII to I directly. In the quoted song, the melody is 3-2-3-4-5; the 2 and 4 are n icely harmonized by the B7 (as well as IV and ii) and most "irregularities" get "justified" by scalar melodies. It's also the Neapolitan of vi or the Augmented Sixth of ii but it's not used that way here.
    – ttw
    Dec 26, 2020 at 2:02
  • I don't see any benefit in muddying up a clear concept such as diatonic. This question will stop reappearing when the site automatically analyzes the posted chords and notes, and is able to detect a bVII chord. Dec 26, 2020 at 14:20
  • It doesn’t even have to be “jazz tinged”, although I do like that term. Check this out: icce.rug.nl/~soundscapes/VOLUME22/… Dec 26, 2020 at 17:46

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