Locrian Mode
The mode nobody writes in, and for a specific reason: the chord on its own root is diminished, so the place you are supposed to call home is the least stable chord there is. That does not make it useless, but it does make it a mode you visit rather than live in.
- 7 notes
- 1 b2 b3 4 b5 b6 b7
- the flattened fifth
which styles use it
- Jazz
- Metal
- Film music
How it is built
Take natural minor and flatten both the second and the fifth. In C that means D flat and G flat. On the white keys, Locrian runs from B to B. Losing the perfect fifth is what breaks it: without that interval the root has nothing holding it up.
Unstable and unresolved, all the way through. Every other mode gives your ear somewhere to stand, and this one does not.
Where to use it
Over half-diminished chords, which is where the scale genuinely earns its place in jazz. In metal, where a few bands have made whole passages work by leaning on the instability rather than fighting it. Rarely anywhere else.
The chords that go with it
The chord on the first degree is half-diminished, which is the problem and also the use. If you need a scale to play over an m7 flat 5, this is the one that fits by default.
What it gets confused with
With the half-diminished chord, which is the practical way most players meet it. Thinking of Locrian as a chord scale rather than a key is the version that actually works.