Harmony
Tritone substitution
Tritone substitution replaces a dominant seventh chord with the dominant seventh whose root is a tritone away, for example D♭7 instead of G7 before Cmaj7.
What is a tritone substitution?
It is the most famous substitution in jazz: you replace a dominant seventh chord with another dominant seventh whose root is a tritone away (three whole steps, six half steps). G7 becomes D♭7, C7 becomes G♭7, D7 becomes A♭7.
In a ii-V-I in C, Dm7 G7 Cmaj7 becomes Dm7 D♭7 Cmaj7. The bass no longer jumps in fifths: it walks down in half steps, D, D♭, C.
Why does tritone substitution work?
Because both chords share the same tritone, the two notes that create the tension:
- G7 = G B D F: the tritone is B and F.
- D♭7 = D♭ F A♭ C♭: the tritone is F and C♭, and C♭ sounds exactly like B.
The third of one chord is the seventh of the other. Those two notes resolve the same way, to C and E. The other notes of D♭7 (D♭ and A♭) are the flat fifth and flat ninth of G7, so D♭7 sounds like an altered G7, with a dark, sophisticated colour close to an altered dominant.
How to play a tritone substitution on guitar
Simple version, roots on the 5th string:
- Dm7: x5756x
- D♭7: x4646x
- Cmaj7: x3545x
Your first finger steps down from fret 5 to 4 to 3 on the A string, and the chromatic bass line jumps out.
Jazz version with ninths, even smoother: Dm9 x53555, D♭9 x43444, Cmaj9 x32433. Your fingers slide almost as a block from fret to fret. Play Dm7 G7 Cmaj7 first, then the substituted version, and compare: same destination, smoother road.
Where should you use tritone substitution?
- On any V7 that resolves: C7 to F becomes G♭7 to F. That is exactly what the chord changes of "The Girl from Ipanema" do with their G♭7 before Fmaj7.
- On secondary dominants: C A7 Dm7 G7 becomes C E♭7 Dm7 D♭7 C, a classic reharmonization.
- In blues: at the end of a progression in A, play B♭7 before A7 instead of E7.
When soloing over D♭7, D♭ Lydian dominant contains the same notes as the G altered scale. The chord substitutions module suggests the tritone substitution of every dominant with playable voicings.
Key takeaways
- Replace a V7 with the V7 a tritone away: G7 becomes D♭7.
- It works because both chords share the same tritone (B and F).
- The bass then moves down in half steps: Dm7 D♭7 Cmaj7.
- It applies only to dominant chords, primary or secondary.
Frequently asked questions
What is the tritone substitution for G7?
D♭7 (also written C#7). Both chords have the same tritone (B and F, spelled C♭ and F in D♭7). The other pairs are C7 and G♭7, D7 and A♭7, A7 and E♭7, E7 and B♭7: each replaces the other.
Can you use a tritone substitution on a minor chord?
Not strictly: the technique relies on the tritone inside a dominant chord. You can, however, substitute the whole ii-V: Dm7 G7 becomes A♭m7 D♭7, often called a substitute ii-V.
Is tritone substitution only for jazz?
No. It shows up in soul, bossa nova and blues, usually at the end of a phrase. A D♭7 or D♭9 before C, or a B♭7 before A in a blues, adds a jazzy colour without changing the melody.
Related terms
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