Backdoor progression

In jazz and jazz harmony, the chord progression from iv⁷ to I, or flat-VII⁷ (VII) to I has been nicknamed the backdoor progression or the backdoor ii-V. This name derives from an assumption that the normal progression to the tonic (V⁷ to I, or the authentic cadence) is, by inference, the front door. Backdoor ii-V refers to VII serving as a substitute for V in the ii-V-I turnaround.

The backdoor ii-V is considered a "bluesy" cadence and IV-VII-I is used repeatedly as a chord substitution, along with tritone substitution, in "Lazy Bird", John Coltrane's arrangement of Tadd Dameron's "Lady Bird.

The backdoor progression can be found in popular jazz standards in such places as measures 9 and 11 of "My Romance" or measures 10 and 28 of "There Will Never Be Another You", as well as Beatles songs like In My Life and "If I Fell". It can be considered a minor plagal cadence in traditional theory.

The flat-VII⁷ chord, a pivot chord borrowed from the parallel minor of the current key, is a dominant seventh. Therefore it can resolve to I; it is commonly preceded by IV going to iv, then flat-VII⁷, then I.

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