Locrian Mode
Locrian is a minor mode with a flat second and flat fifth. C Locrian contains G flat instead of the perfect fifth G, so its tonic triad is diminished and its tonic seventh chord is Cm7 flat 5. That structure shapes how the mode is used.
- 1-flat 2-flat 3-4-flat 5-flat 6-flat 7
- flat fifth
- half-diminished tonic
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How do you build Locrian?
Use the formula:
1-flat 2-flat 3-4-flat 5-flat 6-flat 7
C Locrian is:
C-D flat-E flat-F-G flat-A flat-B flat-C
You can derive it from C Phrygian by lowering degree 5 or from D-flat major with C as tonic.
Which notes identify Locrian?
D flat forms the flat second, and G flat forms the diminished fifth above C.
C-E flat-G flat creates a diminished tonic triad. Add B flat and you get Cm7 flat 5.
The missing perfect fifth is the main structural difference from the other minor modes.
Which chords occur in Locrian?
Stack thirds from C Locrian:
- i diminished: C diminished
- flat II: D-flat major
- flat iii: E-flat minor
- iv: Fm
- flat V: G-flat major
- flat VI: A-flat major
- flat vii: B-flat minor
The seventh chord on C is half-diminished: C-E flat-G flat-B flat.
Can Locrian have a tonic?
Yes. A tonic is established by musical emphasis, not by a requirement that its triad be major or minor.
A C drone, repeated Cm7 flat 5 and phrase endings on C can make C central.
The diminished fifth reduces the acoustic and harmonic stability familiar from major or minor tonic triads, so composers must reinforce the center through other means.
How is Locrian used over half-diminished chords?
C Locrian matches Cm7 flat 5 and adds D flat, F and A flat as scale tones.
In a minor ii-V-i progression, the half-diminished chord often functions as ii rather than tonic. For example, Bm7 flat 5-E7-Am places B Locrian-type material over a moving chord.
Using Locrian over one chord does not make the whole piece Locrian.
What is Locrian natural 2?
Locrian natural 2 raises degree 2.
C Locrian natural 2 is C-D-E flat-F-G flat-A flat-B flat. It is mode 6 of E-flat melodic minor.
Jazz players often prefer it over Cm7 flat 5 when D natural functions as the natural 9. Check the chord symbol and melody before choosing between D flat and D.
How is it different from Phrygian?
C Phrygian has G natural and a Cm tonic triad. C Locrian lowers G to G flat and creates C diminished.
All other notes match.
Compare Cm with C diminished, then compare Cm7 with Cm7 flat 5.
Where is Locrian used?
Locrian appears most often as a chord scale over half-diminished harmony in jazz and classical minor-key progressions.
Some metal, experimental and film music sustains Locrian centers through drones, riffs or repeated diminished-tonic sonorities.
Its rarity as a long-term tonic does not make the interval collection invalid; it makes tonic reinforcement especially important.
How should you practice it?
Hold C and alternate G with G flat.
Play Cm7, then lower G to G flat for Cm7 flat 5. Identify the tritone C-G flat.
Compare C Locrian with C Locrian natural 2 over Cm7 flat 5 and decide which second appears in the melody or chord context.