What is Tritone Substitution?

Tritone substitution is a harmonic technique commonly used in jazz and modern music where a dominant seventh chord is replaced with another dominant seventh chord that is a tritone away from the original root. Because the two chords share the same important guide tones—the third and the seventh—they can function in a similar way within a chord progression.

For example, in the key of C major, the dominant chord is G7, which normally resolves to C major. A tritone substitution replaces G7 with D♭7, because the root of D♭ is a tritone away from G. Both chords contain similar tension tones that lead naturally to the tonic chord, allowing the substitution to work smoothly.

Tritone substitution is widely used in jazz harmony to create smoother bass movement and add harmonic color. It can also introduce chromatic motion into chord progressions, making the music sound more sophisticated and interesting. Because of its distinctive sound and flexibility, tritone substitution is an important concept in advanced harmony and improvisation.