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The 5 Core Jazz Chord Families
The 5 Core Jazz Chord Families
Adding the 4th Note: How the 7th Works
Adding the 4th Note: How the 7th Works
In our last lesson, you learned all 4 basic triad types — Major, Minor, Diminished, and Augmented — each built by stacking thirds: Root → 3rd → 5th. Now we add one more layer — a fourth note stacked the exact same way, one more third above the 5th. This new note is called the 7th, because it sits seven scale-steps above the root.
This single addition is what transforms a simple triad into the rich, sophisticated sound of jazz harmony. Once you know these 5 chord families, you'll be able to recognize and play the vast majority of harmony found in any jazz standard.
Two Versions of the 7th
Just like the 3rd could be Major or minor and change the whole character of the chord, the 7th also comes in two versions:
Major 7th: 11 semitones above the root — close to the root, creates a smooth, stable color
minor 7th (written as b7): 10 semitones above the root — one semitone lower, creates more tension and a bluesy, jazzy pull
An Easier Way to Find It: Count Down from the Octave
Counting up 10 or 11 semitones from the root can feel slow. Here's a faster trick: start from the octave (the root note one octave higher) and count downward instead.
Major 7th: just one semitone below the octave (C → B is one semitone down)
minor 7th: one whole tone below the octave (C → Bb is one tone down)
Both methods land on the exact same note — counting up from the root, or counting down from the octave. Use whichever feels faster on the keyboard for you.
Seeing It on a C Chord
Notice the pattern: exactly like E vs Eb decided Major vs minor earlier, B vs Bb decides Major 7th vs minor 7th now. Same logic, one octave higher.
💡 Why this matters: every chord family below is built from the same triads you already know (Major or minor), with one of these two 7ths added on top. Once you see the pattern, you're not memorizing five random shapes — you're combining things you already understand.
The One-Semitone Chain
The One-Semitone Chain
Just like the 4 basic triads, all 5 chord families are connected by moving just one note at a time. Start with a Major 7 and walk the whole chain down:
Major 7 → Dominant 7: lower the 7th (B → Bb)
Dominant 7 → Minor 7: lower the 3rd (E → Eb)
Minor 7 → Half-Diminished: lower the 5th (G → Gb)
Half-Diminished → Diminished 7: lower the 7th again (Bb → A)
Notice the pattern: C - E - G - B → C - E - G - Bb → C - Eb - G - Bb → C - Eb - Gb - Bb → C - Eb - Gb - A. Four single-note moves take you through all 5 families — you're not memorizing five unrelated shapes, you're learning one shape with four small variations.
Major 7th
Major 7th
Cmaj7 / C∆
Bright and stable sound. The primary resolution chord for major keys.
Notes (C): C - E - G - B
Formula: Root - 3 - 5 - 7
Dominant 7th
Dominant 7th
C7
The chord of tension. Its tritone creates the drive to resolve to the I chord.
Notes (C): C - E - G - Bb
Formula: Root - 3 - 5 - b7
Minor 7th
Minor 7th
Cm7 / C-7
Soft and melancholic. Typically functions as the II degree in major cadences.
Notes (C): C - Eb - G - Bb
Formula: Root - b3 - 5 - b7
Half-Diminished
Half-Diminished
Cm7b5 / Cø
Dark and unstable. Found as the II chord in minor key II-V-I progressions.
Notes (C): C - Eb - Gb - Bb
Formula: Root - b3 - b5 - b7
Diminished 7th
Diminished 7th
Remember the Diminished triad from our last lesson (C - Eb - Gb)? Adding a 7th to it gives us this chord.
Remember the Diminished triad from our last lesson (C - Eb - Gb)? Adding a 7th to it gives us this chord.
Cdim7 / C°
Highly symmetrical and tense. Used for chromatic passing movements.
Notes (C): C - Eb - Gb - A
Formula: Root - b3 - b5 - bb7
Quick Reference Guide
Quick Reference Guide
What's Next
What's Next
You now know the 5 essential chord families used throughout jazz piano. The next step is learning how these chords are voiced and applied on real standards — exactly what you'll find in our full courses.
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