The backdoor progression

The books behind this page

One device, explained on one page. Jazz Harmony is the whole vocabulary in one place: what each resource is, how it is built, when it is used, why it works — and what it does to what the listener expects.

Start here Project 03 · Harmony

Jazz Harmony

From tradition to the expectation framework · For any instrument Project 05 · Harmony

Harmonic Narrative

A practical method for creating and understanding harmonic progressions through expectation Project 04 · Jazz guitar

Jazz Guitar Comping

Creating direction through harmony, rhythm and the expectation framework

Why it resolves without a leading tone

A normal dominant resolves because of its tritone: in G7, B and F squeeze inward onto C and E. Bb7 has a tritone too — D and Ab — but it points somewhere else entirely. What resolves here is different: the Ab falls a semitone to G, the fifth of the tonic, and the Bb falls a semitone to A, or holds and becomes the b7 colour that the arrival keeps.

So the arrival is real, but it is built out of downward semitones rather than out of a leading tone rising into the tonic. That is precisely why it sounds warm instead of conclusive: nothing under the chord is pushing upward. A backdoor cadence closes a phrase the way a sentence ends with a comma that everyone agrees to treat as a full stop.

Compared with the front door

• ii-V-I — the bass drops a fifth into the tonic, a leading tone rises, and the cadence sounds finished.
• Backdoor — the bass rises a whole tone, two upper voices fall by semitone, and the cadence sounds arrived-at rather than concluded.
• Both together — many tunes use the backdoor in the middle of a form and save the real V-I for the end, because only one of the two can close the door.

Standards featuring backdoor progressions (4)

Every tune below is here because the analyzer found this device in the excerpt printed on its page — not because someone decided the tune belongs in this category. Each row links to the full analysis.

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