The Foundation of Jazz Harmony

Seventh chords form the backbone of jazz harmony, adding rich color and complexity to music that basic triads simply cannot provide. While there are many extended and altered chord types in jazz, these five fundamental seventh chords are the essential building blocks that every musician should master.

Each of these chord types has a distinctive sound and function in music, and learning to recognize and play them in all 12 keys will dramatically improve your understanding of harmony, your ability to play by ear, and your improvisational skills.

The Five Essential 7th Chord Types

1. Major 7th Chord (M7, maj7)

The major seventh chord combines a major triad with a major seventh interval. It creates a lush, sophisticated sound often associated with gentle jazz ballads and contemplative musical moments. In jazz, major seventh chords commonly function as the I chord in major keys and the IV chord in major keys.

Formula: 1 - 3 - 5 - 7 (Root, Major 3rd, Perfect 5th, Major 7th)

Example: CM7 = C - E - G - B

2. Dominant 7th Chord (7)

The dominant seventh chord combines a major triad with a minor seventh interval. It creates a strong sense of tension that wants to resolve, making it perfect for the V chord in a key. The dominant seventh is perhaps the most important chord type in jazz, as it drives chord progressions forward and can be altered in countless ways.

Formula: 1 - 3 - 5 - ♭7 (Root, Major 3rd, Perfect 5th, Minor 7th)

Example: C7 = C - E - G - B♭

3. Minor 7th Chord (m7, min7)

The minor seventh chord combines a minor triad with a minor seventh interval. It has a smooth, mellow quality that can be wistful or contemplative. In jazz, minor seventh chords typically function as the ii and vi chords in major keys, and as the i, iv, and v chords in minor keys.

Formula: 1 - ♭3 - 5 - ♭7 (Root, Minor 3rd, Perfect 5th, Minor 7th)

Example: Cm7 = C - E♭ - G - B♭

4. Minor 7th Flat 5 Chord (m7♭5, half-diminished)

Also known as the half-diminished chord, the minor 7th flat 5 combines a diminished triad with a minor seventh interval. It has a distinctive dark, unstable sound that creates beautiful tension. In jazz, it often appears as the ii chord in minor keys, playing a crucial role in minor ii-V-i progressions.

Formula: 1 - ♭3 - ♭5 - ♭7 (Root, Minor 3rd, Diminished 5th, Minor 7th)

Example: Cm7(♭5) = C - E♭ - G♭ - B♭

5. Diminished 7th Chord (°7, dim7)

The fully diminished seventh chord consists of stacked minor thirds, combining a diminished triad with a diminished seventh. It has a highly unstable, tense sound that strongly desires resolution. The diminished seventh chord is often used as a passing chord, as a substitute for dominant chords, or as a pivot chord for modulation.

Formula: 1 - ♭3 - ♭5 - ♭♭7 (Root, Minor 3rd, Diminished 5th, Diminished 7th)

Example: C°7 = C - E♭ - G♭ - B♭♭ (A)

Understanding Chord Relationships

One of the most valuable aspects of studying these five chord types side by side is understanding their relationships:

• Between Major 7th and Dominant 7th: Only one note changes - the major 7th (B in CM7) lowers by a half step to become the minor 7th (B♭ in C7).
• Between Dominant 7th and Minor 7th: Only one note changes - the major 3rd (E in C7) lowers by a half step to become the minor 3rd (E♭ in Cm7).
• Between Minor 7th and Minor 7th Flat 5: Only one note changes - the perfect 5th (G in Cm7) lowers by a half step to become the diminished 5th (G♭ in Cm7♭5).
• Between Minor 7th Flat 5 and Diminished 7th: Only one note changes - the minor 7th (B♭ in Cm7♭5) lowers by a half step to become the diminished 7th (A in C°7).

This progressive "lowering" of tones creates a logical sequence that makes these chords easier to understand and remember.

Practical Applications in Jazz

These five seventh chords appear in distinct harmonic contexts:

• In Major Keys: The I chord is typically Major 7th, the ii and vi chords are Minor 7th, the V chord is Dominant 7th, and the vii chord is Minor 7th Flat 5.
• In Minor Keys: The i and iv chords are typically Minor 7th, the ii chord is Minor 7th Flat 5, the V chord is Dominant 7th (borrowed from harmonic minor), and the vii chord is often a Diminished 7th.
• In ii-V-I Progressions: The progression typically uses Minor 7th for the ii, Dominant 7th for the V, and Major 7th for the I.
• In Jazz Blues: Dominant 7th chords predominate, with occasional Minor 7th chords as the ii in ii-V turnarounds.

Practice Strategies for Mastery

To truly internalize these chord types, consider these practice approaches:

1. Horizontal Practice: Practice one chord type through all 12 keys, following the circle of fifths (e.g., all Major 7th chords: CM7 → GM7 → DM7, etc.).
2. Vertical Practice: Practice all five chord types with the same root, focusing on the slight changes between each type (e.g., CM7 → C7 → Cm7 → Cm7♭5 → C°7).
3. Chord Progressions: Practice these chords in common progressions like ii-V-I in all keys.
4. Voice Leading: Practice moving between these chords with smooth voice leading, keeping note movement to a minimum.
5. Ear Training: Practice identifying these chord types by ear, both individually and in musical contexts.

Use our interactive exercise above to drill these concepts and build your seventh chord fluency in all keys!