Modes

The Locrian Mode

Locrian is the 7th and final mode of the major scale, and the most extreme. It is the only mode with a diminished 5th, which makes it almost impossible to use as a stable tonal center. Understanding why it is so unstable teaches you a lot about how harmony works.

Explore Locrian on the fretboard

Load B Locrian in Scale Mapper and hear what maximum harmonic tension sounds like across the neck.

Open B Locrian →

What is Locrian?

Locrian is the 7th mode of the major scale. It is built on the 7th degree. In C major, that is B Locrian: B C D E F G A. Compared to natural minor, Locrian has two extra flats: both the 2nd and the 5th are lowered. That flat 5th is the key problem.

B natural minor: B C# D E F# G A

B Locrian: B C D E F G A

Red = flat 2nd and flat 5th. The diminished 5th is what makes Locrian impossible to stabilize.

Why the flat 5th is such a problem

In almost every other mode, the 5th degree is a perfect 5th, a stable, consonant interval that reinforces the root and makes the tonal center feel grounded. In Locrian, the 5th is diminished, a tritone above the root. The tritone is the most dissonant interval in western music.

This means the chord built on the Locrian root is a diminished chord: root, minor 3rd, diminished 5th. A diminished chord has no stable 5th to anchor it. It wants to move. It cannot sit still. That is why Locrian is nearly impossible to use as a sustained tonal center. The home chord itself sounds unstable and wants to resolve somewhere else.

Where Locrian actually appears

Despite its instability, Locrian does appear in real music, just rarely as a tonal center. More often, it shows up as a passing color or over a specific chord in a progression.

Over the vii° chordIn any major key, the 7th chord is diminished. Locrian is the natural mode to play over it. In C major, that is Bdim. Play B Locrian.

Metal and extreme musicThe instability and darkness of Locrian fit extreme metal contexts. Slayer, Meshuggah, and avant-garde metal composers use Locrian-flavored sounds for maximum tension.

Brief passing sectionsComposers use Locrian for a bar or two to create extreme tension before resolving back to a stable mode. It is a dramatic device, not a home base.

Theoretical completenessLearning Locrian rounds out your understanding of the modal system. Even if you rarely use it, knowing why it is unstable deepens your understanding of harmony.

Hear Locrian on the neck

Load B Locrian in Scale Mapper. Find the flat 5th (F natural) and hear the tritone tension it creates.

Open B Locrian →

Locrian vs the other dark modes

If you want dark and aggressive, Phrygian is more usable than Locrian. Phrygian has a perfect 5th, which means its home chord is a stable minor chord. It can function as a genuine tonal center. Locrian cannot.

Think of the modes on a spectrum from brightest to darkest: Lydian, Ionian (major), Mixolydian, Dorian, Aeolian (natural minor), Phrygian, Locrian. Locrian sits at the extreme dark end, further than most music ever goes. Phrygian is the dark mode that is actually practical. Locrian is the theoretical endpoint.

Should you learn Locrian?

Yes, not because you will use it constantly, but because it teaches you something important. The reason harmony works the way it does is because the perfect 5th is stable. Locrian shows you what happens when you remove that stability entirely. Understanding Locrian makes you understand why every other mode sounds the way it does.

Load it in the Scale Mapper, play it, and listen. The instability you feel is the theory working exactly as described.

Explore Locrian across the full neck

Load B Locrian in Scale Mapper and see every note mapped across all 24 frets. Compare it to B natural minor to hear exactly what the flat 5th changes.

Open B Locrian in Scale Mapper →