The Backdoor ii–V

In C major

Fm7 – Bb7 – Cmaj7 — warm, unexpected, gospel-adjacent, around 120 BPM.

1. Bar 1 ivm7 Fm7
   F · Ab · C · Eb
   ▶ Hear it
2. Bar 2 bVII7 Bb7
   Bb · D · F · Ab
   ▶ Hear it
3. Bar 3 Imaj7 Cmaj7
   C · E · G · B
   ▶ Hear it

Why it works

The pair is the ii–V of the flattened third, but instead of resolving there it lands on the tonic. It works because ♭VII7 contains the flattened seventh and the fourth of the home key, and both resolve by step into the tonic chord: one rises a whole step to the root, the other falls to the third. Arriving from a whole step below rather than a fifth above is what gives it its characteristic softness.

Where you'll hear it

As a substitute for a plain IV–I, or as an alternative approach the second time a phrase repeats. It is the standard way to make a IV chord do something more than sit there.

ivm7–♭VII7–Imaj7 in every key

The same progression transposed. The roman numerals never change — that is the whole point of writing progressions this way.

Related progressions

• iim7–♭II7–Imaj7 The Tritone Substitution
• iim7–V7–Imaj7 The ii–V–I Progression
• I–♭VII–IV The Mixolydian Rock Progression