The Bebop Locrian scale (also known as the Half-Diminished Bebop scale) is an eight-note scale designed to navigate half-diminished chords in jazz. By adding a chromatic passing tone to the standard Locrian mode, it ensures that the essential chord tones of a m7♭5 chord align perfectly with the downbeats of a swing rhythm.
Construction and formula
The Bebop Locrian scale is built by adding a natural 5th as a chromatic passing tone to the standard Locrian mode. This fills the gap between the ♭5 and the ♭6.
In C, the notes are: C–D♭–E♭–F–G♭–G–A♭–B♭.
Its interval formula is: 1–♭2–♭3–4–♭5–5–♭6–♭7.
This eight-note configuration allows the primary chord tones (1, ♭3, ♭5, ♭7) to fall consistently on strong beats when playing continuous eighth-note lines.
Musical usage
This scale is specifically used over minor 7♭5 chords, which typically function as the ii chord in a minor ii–V–i progression. Its primary role is to provide melodic "logic" to the Locrian sound, which can often feel unstable or directionless in a linear context.
The natural 5 acts as a rhythmic "spacer." It is not intended to function as a harmonic resting point, but rather as a connector that preserves the forward momentum of a jazz line while maintaining the dark, diminished quality of the mode.
Examples
- Jazz improvisation over minor ii–V–i progressions (played over the m7♭5 chord).
- Eighth-note runs in standards like "Autumn Leaves," "Stella by Starlight," or "Blue Bossa."
- Linear patterns that require the ♭7 and ♭5 to land on downbeats for harmonic clarity.
- Practice drills transitioning from the ii (Bebop Locrian) to the V (Bebop Dominant).
In practice
Practice a standard Locrian scale in eighth notes and notice how the chord tones eventually shift to the "and" of the beat. Then, insert the natural 5 between the ♭5 and ♭6 to see how the root, ♭3, and ♭5 instantly snap back onto the downbeats.
In a performance context, use the natural 5 strictly as a passing tone. Do not pause on it, as the ♭5 must remain the defining harmonic color of the chord.
