Major I-VI-ii-V Progression in Bb

Tritone substitutes

Bbmaj7 Db7 Cm7 B7

Each dominant 7th that resolves down a fifth becomes the dominant a tritone away, which shares its 3rd and 7th, so the bass moves by half steps.

Related ii chords

Bbmaj7 Dm7b5 G7 Cm7 F7

Each dominant 7th gets the ii chord of its own ii-V before it, half a dominant's time each.

Backdoor dominants

Bbmaj7 G7 Ebm7 Ab7

Each V7 resolving to a major chord comes in by the back door from bVII7, with iv7 for its ii, borrowed from the minor key.

Passing diminished chords

Bbmaj7 Bdim7 Cm7 F7

Diminished 7ths on the half steps between chords a whole step apart, or in place of a dominant whose 3rd is a half step above the chord before.

Major I-vi-ii-V

Imaj7 vi7 | ii7 V7

In Bb: Bbmaj7 Gm7 Cm7 F7

The basic turnaround: diatonic chords falling in fifths from vi back to I, two to a bar, to bring a tune back to the top.

Major iii-VI-ii-V

iii7 VI7 | ii7 V7

In Bb: Dm7 G7 Cm7 F7

The I-VI-ii-V turnaround with iii, which shares three notes with the I chord, standing in for the tonic.

Diminished Passing Turnaround

Imaj7 ♯i°7 | ii7 V7

In Bb: Bbmaj7 Bdim7 Cm7 F7

The I-VI-ii-V with a diminished 7th chord on #I in place of VI7, so the bass rises by half steps from I to ii.

Tritone Sub Turnaround

Imaj7 ♭III7 | ii7 ♭II7

In Bb: Bbmaj7 Db7 Cm7 B7

The I-VI-ii-V with tritone substitutes for its dominants, bIII7 for VI7 and bII7 for V7, so the bass falls by half steps from bIII back to I.

Chromatic iii-bIII-ii-bII

iii7 ♭III7 | ii7 ♭II7

In Bb: Dm7 Db7 Cm7 B7

The iii-VI-ii-V turnaround with both dominants replaced by tritone substitutes, so the roots descend by half steps from iii to I.

Tadd Dameron Turnaround

Imaj7 ♭IIImaj7 | ♭VImaj7 ♭IImaj7

In Bb: Bbmaj7 Dbmaj7 Gbmaj7 Bmaj7

A turnaround of major 7th chords on I, bIII, bVI and bII, named after the bebop composer and arranger Tadd Dameron.