Tritone substitution progressions

Guitar background progression indicated The tritone substitution is a relative common feature in especially jazz. How this feature are used and why is explained by various analyzed examples.

Tritone is the name of the interval made up of three whole steps. For example C to G# (Ab) or G to C# (Db).

Substitution means that a chord is substituded (replaced) for another that normally isn't involved. For example is G7 often followed by C7, but by suing a tritone substitution C7 would insted be C#7 in this case. This change can also be written as I7 - #V7.

Some examples of a progression inclduing a tritone substitution:

C7 - G#7 (G#7 is the tritone substitution chord)
D7 - A#7 (A#7 is the tritone substitution chord)
E7 - C7 (C7 is the tritone substitution chord)
G7 - C#7 (C#7 is the tritone substitution chord)

In a song the tritone substitution may consist of a half bar and it could look like this:

G7 C#7

C#7 can be seen as the tension chord that is resolved by C7 before turning home to the I chord.

Or as a part of a turnaround:

Am7

C#7

Here, C#7 replaces the more expected D7.

The tritone substitution can also be used in a progression with a chromatic motion:

Dm7 – C#7 – Cmaj7 (iim7 – #I7 – Imaj7)

Dm7 is the tritone substitution chord in this case (and replaces the more exppected G7).

ii - V - I with tritone substitutions in all keys

The V chord is substituted for another V chord, which root is a tritone interval away.

Key	ii	V	I
C	Dm7	Db7	Cmaj7
E	F#m7	F7	Emaj7
A	Bm7	Bb7	Amaj7
D	Em7	Eb7	Dmaj7
G	Am7	Ab7	Gmaj7
F	Gm7	Gb7	Fmaj7
B	C#m7	C7	Bmaj7
Bb	Cm7	B7	Bbmaj7
Eb	Fm7	E7	Ebmaj7
Ab	Bbm7	B7	Abmaj7
Db	Ebm7	E7	Dbmaj7
Gb	Abm7	A7	Gbmaj7
C#	D#m7	D7	C#maj7
D#	Fm7	E7	D#maj7
F#	G#m7	G7	F#maj7
G#	A#m7	A7	G#maj7
A#	Cm7	B7	A#maj7

Only seventh chords are mentioned in the table and in other examples, but it is possible to use 9th and 13th chords instead as well as altered chords.