Diatonic and mediant substitutions
Exchange closely related diatonic chords to change bass, density, and tonic emphasis while preserving common tones.
Interactive listening
Hear the harmony in time
Compare the examples at one tempo.
Tonic in the bass
Cmaj7 states the key clearly with C under the shared E–G–B upper structure.
iii substitutes for I
Em7 retains E–G–B but replaces the tonic root with D, softening the sense of arrival.
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Diatonic chord substitutions in jazz guitar
See how chords with related functions and shared notes can enrich an accompaniment without obscuring the tune.
Open on YouTube (opens in a new tab)Similarity is not identical function
Cmaj7 and Em7 share E, G, and B; Cmaj7 and Am7 share C, E, and G. That overlap lets iii or vi prolong a broad tonic area, especially when the melody uses common tones. The substituted bass note changes the weight and direction even when the upper voices barely move.
Calling these chords substitutes does not mean they are interchangeable everywhere. I has the strongest tonic identity. iii can connect I toward vi or IV, while vi often creates motion toward ii. Context determines whether the ear hears prolongation, departure, or a genuine change of function.
Arrange from the melody downward
Hold the melody note, list the diatonic seventh chords that contain it, then compare their bass motion into the next chord. A successful substitution supports both the tune and the phrase direction.
Smooth voice leading is a result of keeping common tones and moving remaining voices by step. On guitar, look for a nearby inversion instead of jumping to a new root-position grip.
- Imaj7 and iii7 share scale degrees 3, 5, and 7.
- Imaj7 and vi7 share scale degrees 1, 3, and 5.
- Use common tones as anchors, but judge function from the whole phrase.