Lesson 60 · All 12 keys

Split-Third Blues Chord Trainer

Learn how a Split-third "blues" chord is built one semitone-count at a time — a dominant 7th chord (Lesson 13) with both the minor 3rd and major 3rd sounded together, instead of just the major 3rd — then put it to work with three MIDI exercises: playing all 12 split-third "blues" chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions that show off its color, in every key.

How a Split-third "blues" chord is built

A Split-third "blues" chord — written 7(♭3/♮3) (e.g. C7(♭3/♮3)) — is a 5-note chord: a dominant 7th chord (Lesson 13) with both the minor 3rd and major 3rd sounded together, instead of just the major 3rd. Every 7(♭3/♮3) chord — in any of the 12 keys — is built the exact same way, by counting semitones to the right from a root note:

  1. The starting note — this note names the chord.
  2. Count 3 semitones up from the root — the minor 3rd (the "blue" 3rd).
  3. Count 1 more semitone up from the minor 3rd (4 semitones from the root) — the major 3rd, sounded right alongside it rather than instead of it.
  4. Count 3 more semitones up from the major 3rd (7 semitones from the root) — the perfect 5th.
  5. Count 3 more semitones up from the 5th (10 semitones from the root) — the minor 7th, the same 7th a plain dominant 7th chord (Lesson 13) uses.
Example — C7(♭3/♮3): start on C, count 3 semitones right to reach E♭, count 1 semitone more to reach E, count 3 semitones more to reach G, count 3 semitones more to reach B♭. C‑E♭‑E‑G‑B♭ is the C7(♭3/♮3) chord.
This is the classic "crushed 3rd" of blues and gospel piano: both the minor and major 3rd struck together, a half step apart, rather than picking one. It works anywhere a dominant 7th chord (Lesson 13) would, just with extra blues grit.

Try it: pick a root and build the chord step by step

Step 1 of 5
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Chord toneNoteSemitones from rootMIDI #

All 12 split-third "blues" chords at a glance

ChordRootMinor 3rdMajor 3rdPerfect 5thMinor 7th

This MIDI exercise plays all 12 split-third "blues" chords, one after another, moving around the circle of fourths — each chord's root sits a perfect 4th (5 semitones) above the last one: C → F → B♭ → E♭ → A♭ → D♭ → G♭/F♯ → B → E → A → D → G → back to C. Every chord is played as a full 5-note Split-third "blues" chord (root, minor 3rd, major 3rd, perfect 5th, minor 7th together).

Chord 1 of 12
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The 12 chords, in circle-of-fourths order

#ChordRootMinor 3rdMajor 3rdPerfect 5thMinor 7th

Five jazz chord progressions built around the Split-third "blues" chord. Pick a progression and play it in one key or cycle through all 12.

Key of C
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Progression in C

DegreeChordNotes

Five gospel chord progressions built around the Split-third "blues" chord. Pick a progression and play it in one key or cycle through all 12.

Key of C
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Progression in C

DegreeChordNotes