The Diminished Chord & Its Function in Jazz Harmony

Welcome to this in-depth workshop on diminished harmony. Instead of focusing on a specific jazz standard, we explore the diminished chord, its role in harmony, and how to use it effectively in improvisation and chord voicings.

Understanding Diminished Harmony

The diminished chord is a fundamental yet complex harmonic structure in jazz. It consists of a symmetrical stack of minor 3rds (e.g., C diminished: C – Eb – Gb – A). Because of this symmetry, a single diminished chord can function in multiple harmonic contexts.

One of the key principles of diminished harmony is that diminished chords always function as dominant chords. For example, C diminished can function as part of an F7 chord, leading to Bbmaj7. This dominant function is at the core of how diminished harmony is used in jazz.

The Relationship Between Diminished & Dominant Chords

A diminished chord is essentially a rootless dominant 7b9 chord. For example, C diminished (C – Eb – Gb – A) contains the 3rd, 5th, 7th, and b9 of an A7 chord, making it function as a dominant. This concept extends to tritone substitution, where the same diminished structure can imply multiple dominant chords, depending on the bass note.

The Four Dominant Chords in Every Diminished Chord

Due to its symmetrical nature, every diminished chord can function as four different dominant 7b9 chords. For example, C diminished can be:

• G7b9 (resolving to C)
• Bb7b9 (resolving to Eb)
• Db7b9 (resolving to Gb/F#)
• E7b9 (resolving to A)

This means that diminished harmony creates multiple resolution possibilities, allowing for reharmonization and chromatic movement within chord progressions.

The Diminished Scale & Its Application

The diminished scale is built by alternating whole and half steps (e.g., C diminished scale: C – D – Eb – F – Gb – Ab – A – B). Instead of thinking of "whole-half" and "half-whole" separately, it’s more effective to see them as one unified structure that works over all four dominant chords related to a given diminished chord.

A useful way to visualize the diminished scale is by seeing it as a dominant bebop scale with chromatic approach tones. This approach makes improvising over diminished chords more intuitive and practical.

Diminished Voicings & Improvisation Tricks

Voicings Derived from the Diminished Structure

One of the most effective ways to voice diminished harmony is by creating drop-2 voicings or spread voicings derived from the diminished scale. A common approach used by pianists like Herbie Hancock and Hank Jones is to use double diminished voicings, which combine both the diminished chord tones and the passing tones from the diminished scale.

Moving Voicings & Lines in Minor 3rds

Since the diminished chord is symmetrical, any voicing or melody built from it can be moved up or down in minor 3rds while maintaining its function. This is a powerful tool for harmonic movement, allowing for sophisticated chromatic passing chords and fluid diminished runs in improvisation.

5 Practice Tips for Mastering Diminished Harmony

1. Identify the Four Dominants – Take any diminished chord and practice identifying its four possible dominant 7b9 resolutions. This will help you apply diminished chords functionally in jazz standards.

2. Practice Diminished Scale Over 2-5-1s – Instead of thinking of separate "whole-half" or "half-whole" scales, practice the single diminished scale that connects both the ii-7 and V7 chords in a 2-5-1 progression.

3. Move Chords & Melodies in Minor 3rds – Play a simple diminished voicing and shift it in minor 3rds up the keyboard. Try applying this concept to melody lines to hear the smooth chromatic motion.

4. Use Diminished Passing Chords – Insert diminished chords as passing chords between dominant chords in jazz standards. For example, use C diminished as a passing chord between Cmaj7 and D-7.

5. Experiment with Diminished Voicings in Solos – Incorporate diminished chord shapes and double diminished voicings into your improvisation, creating tension and resolution within your solos.

Mastering diminished harmony opens up new melodic and harmonic possibilities in jazz improvisation and comping. By internalizing its function as a dominant and exploring symmetrical movements, you’ll gain a deeper understanding of how to reharmonize and enhance jazz standards with diminished chords. Keep practicing, and enjoy exploring the rich sound of diminished harmony!