Tritone substitution

Tritone substitution is a great way of spicing up your jazz chord progressions.

Tritone substitution is where you replace a dominant chord with another dominant chord a tritone (b5th) away from the root. For example you could replace a G7 chord with a Db7 chord (Db is a tritone away from G). This creates a really smooth chordal movement. Thus if you were playing a 2-5-1 progression in C you would get

Dm7-C#7-Cmaj7

instead of the typical

Dm7-G7-Cmaj7

The reason these two chords can be substituted is that they both share two common pitches (the third and the seventh).

The tritone substitution naturally implies an altered type sound so feel free to embelish the substituted dominant chord.

If you look carefully at the chords you will see that a Db9 chord is pretty much functioning as a G7 alt chord in this progression.

Listen to jazz players like Bireli Lagrene and Joe Pass (above) to hear some interesting chord substitutions