Is There a Theoretical Explanation for a Change from Major 7 to Minor 7 Chords with the Same Root in Jazz?

In jazz music theory, the transition from a major 7 (maj7) to a minor 7 (min7) chord sharing the same root is a common and often intriguing technique. This change can be

Understanding the Transition

The theory behind this harmonic movement is not strictly mandated but rather embraced as a creative and expressive tool within the jazz vocabulary. For example, consider the standard progression:

Emin7 - A7 - Dmaj7 - Dm7 - G7 - Cmaj7 - Cmin7 - F7 - Fmaj7

Notice how each major 7 chord changes to a minor 7 on the same root. This progression can also be analyzed as a series of descending ii-V-I progressions moving down in whole steps—from the key of D to C to Bb. Another illustrative example is:

Cmaj7 - Fmaj7 - Fm7 - Cmaj7

Here, the IV chord (Fmaj7) changes to a iv minor chord (Fm7) to return to the I chord (Cmaj7). This chromatic descending pattern (A, Ab, G) provides a satisfying resolution.

The Role of Modal Borrowing

One theoretical approach to this change is through the concept of modal borrowing, which involves borrowing chords from parallel modes or keys. In the case of Fmaj7 and Fm7, Fmaj7 belongs to the key of C major, while Fm7 belongs to the key of C minor. This technique is known as mode mixture or modal interchange.

Practical Examples in Jazz

Let's examine a practical example from the jazz standards repertoire. Consider the progression from measure 9-10 of "Unforgettable" by Irving Gordon from the Real Book:

Fmaj7 - Like a song of/Fm7 love that clings to me Then Cmaj7 - How the...

Here, Fmaj7 changes to Fm7, which serves as the dominant leading to the I chord, Cmaj7. In the 25-26 measures of the 2nd section:

Fmaj7 - That's why darling Fm it's incredible Cmaj7 - that some...

In the Real Book version, the Fm chord is used, but with an E natural on the stressed syllable, it becomes Fm7, enhancing the harmonic resolution and aligning better with the lyrics.

Conclusion

The transition from major 7 to minor 7 chords with the same root is not just a theoretical concept but a practical and expressive tool in jazz. It adds depth, color, and emotional resonance to the music. Whether through modal borrowing, mode mixture, or simple harmonic variation, this change enriches the harmonic landscape of jazz progressions.

Keywords

jazz chord progressions, major 7 to minor 7, modal borrowing