A Locrian Scale: Notes, Chords, and How to Play It

A Locrian is built on the 7th degree of B♭ major and is one of the more accessible Locrian modes for guitarists — the A root on the open 5th string provides a natural anchor for riffs and bass lines. Its diminished tonic triad, flatted 2nd, and flatted 5th make harmonic resolution impossible in the traditional sense. In jazz, A Locrian is the go-to scale over Am7♭5 chords, which appear frequently in ii–V–i progressions in G minor.

What Makes Locrian Different?

The Locrian mode is built on the 7th degree of a major scale. A Locrian uses the notes of B♭ major starting and ending on A. Compared to A natural minor (A Aeolian), Locrian has both a flatted 2nd and a flatted 5th. Those two alterations eliminate the perfect 5th and produce a diminished tonic triad — making Locrian inherently unstable and unsuitable as a conventional key centre.

For a full explanation of all seven modes, see Modes Explained: Dorian to Locrian.

Notes of the A Locrian Scale

The A Locrian scale contains seven notes:

A – B♭ – C – D – E♭ – F – G

The scale follows the Locrian interval pattern — H – W – W – H – W – W – W — and returns to A one octave higher. It contains two flats (B♭ and E♭).

The half steps fall between A–B♭ (degrees 1–2) and D–E♭ (degrees 4–5). The minor 2nd (B♭) and diminished 5th (E♭) are the defining intervals — together they create the grinding, unstable tension that characterises Locrian.

A Locrian on Piano

A Locrian begins on A and immediately steps to B♭ — a black key — establishing the Locrian sound from the very first interval. With only two black keys in the scale, it remains relatively easy to finger.

Right hand fingering (ascending): 1 – 2 – 3 – 1 – 2 – 3 – 4 – 5 (thumb crosses under after C, then fingers walk up to A)

Left hand fingering (ascending): 5 – 4 – 3 – 2 – 1 – 3 – 2 – 1 (after the thumb plays D, the third finger crosses over to E♭)

Practise with a sustained A drone in your left hand. Without it, your ear will gravitate towards hearing B♭ major. The drone anchors A as the tonal centre and reveals the true Locrian darkness.

A Locrian on Guitar

A Locrian sits comfortably in the open position on guitar, with the root on the open 5th string. This makes it one of the most accessible Locrian modes on the instrument.

Open position (low to high):

The half step between the open 5th string and the 1st fret (A to B♭) is the source of Locrian’s menacing character. This ♭2-to-root motion sits right at the nut, making it effortless to exploit in riff-based playing.

Use the guitar fretboard view in the Interactive Chord Finder to see all positions at once.

Diatonic Chords in A Locrian

Stacking thirds on each scale degree produces seven triads with a characteristic Locrian pattern:

The i° chord (Adim) is diminished — there is no stable tonic triad. Locrian establishes its root through rhythmic repetition and pedal tones rather than harmonic resolution.

For a thorough explanation of how diatonic chords are constructed, see Diatonic Chords: A Beginner’s Guide.

Seventh Chords

Adding a fourth note to each triad creates seventh chords, central to Locrian’s role in jazz:

The iø7 chord (Am7♭5) is the half-diminished seventh — the chord most associated with Locrian. In jazz, Am7♭5 is one of the most commonly encountered half-diminished chords, appearing in countless standards in G minor. For more on seventh chords, see Seventh Chords: The Complete Guide.

Locrian in Practice

Because the tonic chord is diminished, traditional chord progressions do not work in Locrian. Instead, Locrian is used in specific contexts:

Metal Riffs and Ostinatos

In extreme metal, djent, and progressive metal, Locrian riffs use the ♭2–root half-step motion (B♭–A) as a grinding, dissonant motif. The riff anchors A through rhythmic repetition rather than harmonic resolution. With the open A string as the root, guitarists can create palm-muted Locrian riffs that exploit the B♭ at the 1st fret for maximum dissonance.

Jazz Over Half-Diminished Chords

In jazz, A Locrian appears whenever an Am7♭5 chord functions as a ii chord in a minor key. In a ii–V–i progression in G minor (Am7♭5 – D7 – Gm), the Am7♭5 chord calls for A Locrian. This is an extremely common progression in jazz standards, making A Locrian one of the most practically useful Locrian keys.

Experimental and Avant-Garde

Composers seeking maximum dissonance and instability turn to Locrian for its refusal to resolve. Film scores, video game soundtracks, and avant-garde compositions use it to create dread and unease.

Parent Major Scale and Modal Relationships

A Locrian is the 7th mode of B♭ major. Every mode of B♭ major shares the same seven notes but starts on a different degree:

Locrian vs Natural Minor

Locrian can be understood as a natural minor scale with two additional alterations — a flatted 2nd and a flatted 5th:

Those two semitone drops — B to B♭ and E to E♭ — remove the only intervals that give natural minor its stability. The result is a mode that cannot settle, cannot resolve, and constantly pulls away from its own root.

Practice Tips

Drone on A. Play or loop a low A note and improvise using the scale over it. Without the drone, your ear will default to hearing B♭ major.

Emphasise the ♭2 and ♭5. When practising, linger on B♭ (the minor 2nd) and E♭ (the diminished 5th). These are the notes that define Locrian.

Practise the ♭2–root riff. Repeatedly play B♭–A in rhythm. On guitar, this is fret 1 to open on the 5th string — a simple but powerful Locrian riff motion.

Play over an Am7♭5 chord. Loop an Am7♭5 chord and improvise with the scale. This is the most practical jazz application and one of the most common half-diminished contexts in the repertoire.

Compare with Phrygian. Play A Phrygian (A – B♭ – C – D – E – F – G) immediately after A Locrian to hear the effect of the ♭5. Phrygian shares the ♭2 but keeps the perfect 5th — the comparison isolates exactly what the diminished 5th contributes to the Locrian sound.

Try It Yourself

Open the Interactive Chord Finder, select A as the root and Locrian as the scale. You will see every note highlighted on the piano keyboard or guitar fretboard, the step pattern visualised as intervals, and all diatonic chords laid out in a table — ready to play and explore.

For the complete list of scales in every key, see Scales for Piano and Guitar: The Complete Reference Guide.