Locrian mode

What it is

Locrian is the seventh mode of the major scale. Its formula: 1, ♭2, ♭3, 4, ♭5, ♭6, ♭7. Compared with the natural minor scale, two notes change: the 2nd and the 5th drop a half step.

The simplest example is B Locrian: B, C, D, E, F, G, A. The white keys starting on B: the same notes as C major, with B as the root.

Its characteristic note

It’s the ♭5 (F, in B Locrian), backed up by the ♭2 (C). The ♭5 is what tips everything over: without a perfect 5th, the root chord is no longer minor but diminished. On the neck, the ♭5 is shown in purple.

Why it’s rare

A key needs a resting point: the root chord. In Locrian, that chord is diminished (B, D, F), a chord that’s tense by nature and always wants to move somewhere else. Your ear never manages to settle on it. As a result, very few songs are truly in Locrian. It’s the mode you’ll use least.

Which chords to use it over

Its real home is the m7♭5 chord, also called half-diminished: B, D, F, A in B. That chord shows up mostly in jazz, in the minor ii–V–i (Bm7♭5 – E7 – Am). Over the Bm7♭5, B Locrian fits perfectly.

To hear it as a mode in its own right, play over a held low B and lean on F and C. The effect is strange and unsettling, and that’s the point.

Where you hear it

• A few metal riffs that go looking for exactly that unease.
• Björk’s “Army of Me” is often cited as an example of a Locrian color.
• In jazz, briefly, over half-diminished chords.

On the neck

To place Locrian among the other modes, go to The modes. All 12 keys are listed below.