Bbm7b5 guitar chord — root mapping, fingerings, arpeggios, triads, pentatonic, scales

Locrian Natural 2 is a half-diminished mode without the Phrygian b2; it is the sixth mode of melodic minor. The natural 2nd acts as a 9th over m7b5 and sounds smoother than regular Locrian, while b5 preserves the half-diminished core. It is a standard choice for iiø in a minor ii – V – i in modern jazz.

Locrian Natural 2 is a minor mode with a natural 2nd and lowered 5th degree. It differs from ordinary Locrian by one note: it uses the major 2nd 2 instead of the minor 2nd b2. The minor 3rd preserves its minor quality, while b5 forms a tritone with the tonic and turns the tonic triad into a diminished chord. The natural 2 functions as the 9 over a half-diminished chord and does not form the minor 9th against the root found in ordinary Locrian. Its defining profile comes from the combination of the natural 2, minor 3rd b3, and diminished 5th b5.

1 — tonic / chord root: the modal center and the root of the diminished i° triad and half-diminished iø7 seventh chord.

2 — major 2nd / 9th: the defining degree that distinguishes the mode from ordinary Locrian. Over iø7 it functions as a natural 9 and serves as the root of the diminished ii° chord.

b3—minor 3rd: establishes the mode’s minor quality, belongs to i° and iø7, and serves as the root of the minor biii chord.

4 — perfect 4th / 11th: functions as the 11 over iø7 and serves as the root of the minor iv chord.

b5—diminished 5th: the principal structural degree of the mode. It forms a tritone with the tonic, belongs to i° and iø7, and serves as the root of the augmented bV+ chord. The perfect 5th 5 is absent.

b6—minor 6th / flat 13th: functions as the b13 over iø7 and serves as the root of the major bVI chord.

b7—minor 7th: belongs to iø7, serves as the root of the major bVII chord, and lies a whole tone below the tonic, so it does not function as a conventional leading tone.

Harmonizing the scale in triads produces:

i° — diminished; ii° — diminished; biii — minor; iv — minor; bV+ — augmented; bVI — major; bVII — major.

The diatonic seventh chords are iø7, iiø7, biii(maj7), iv7, bVmaj7#5, bVI7, and bVII7.

The principal harmonic marker is the half-diminished tonic chord iø7, built from 1 b3 b5 b7. The natural 2 adds the 9, while 4 and b6 supply the 11 and b13.

The iiø7 chord has the same half-diminished quality but is rooted on the natural 2nd degree. The biii(maj7) chord combines a minor triad with a major 7th, while bVmaj7#5 combines an augmented triad with a major 7th.

The bVI7 and bVII7 chords both have dominant seventh quality, but their function depends on the particular progression: they are not automatically dominants of the Locrian tonic.

In C Locrian Natural 2, the triads are Cdim Ddim Ebm Fm Gbaug Ab Bb; the seventh chords are Cm7b5 Dm7b5 Ebm(maj7) Fm7 Gbmaj7#5 Ab7 Bb7.

Locrian Natural 2 is used primarily over half-diminished m7b5 chords when the harmony or melody supports a natural 9. Degrees 1 b3 b5 b7 exactly match the chord tones, while 2 and 4 add the natural 9 and 11. For example, C Locrian Natural 2 may be used over Cm7b5 when the melody contains D rather than Db.

In jazz, the mode is especially associated with the iiø7 chord in a minor iiø7–V7–i progression. Over Dm7b5 in C minor, for example, D Locrian Natural 2 contains D E F G Ab Bb C. This pitch collection is the sixth mode of F Melodic Minor.

Ordinary Locrian also corresponds to m7b5, but contains b2, or b9 relative to the chord root. Locrian Natural 2 is chosen when a natural 9 is required or appears in the melody. The symbol m7b5 alone does not determine the choice completely; chord function, melody, and voice leading provide the necessary context.

As an independent modal scale, it is less common because its tonic triad is diminished and contains no perfect 5th. The center can be reinforced through repeated tonic notes, a tonic bass, a sustained iø7 chord, and melodic figures emphasizing both the natural 2 and b5.

The mode does not fit unchanged when the chord or melody contains a b9 or natural perfect 5th 5. Ordinary Locrian may be more accurate in the first case, while a natural 5 directly conflicts with b5.

Locrian Natural 2 is the sixth mode of Melodic Minor. Its relative parent Melodic Minor scale begins a minor 3rd above its tonic. For example, C Locrian Natural 2 and Eb Melodic Minor contain the same notes, C D Eb F Gb Ab Bb, but C is the center in the former and Eb in the latter.

Its closest parallel mode is ordinary Locrian, 1 b2 b3 4 b5 b6 b7. It differs only in the 2nd degree: Locrian Natural 2 uses a natural 2.

Aeolian has the formula 1 2 b3 4 5 b6 b7 and uses a perfect 5th instead of b5. Locrian Natural 2 is therefore also called Aeolian b5. Another common name is the Half-Diminished Scale.

Locrian ♮6 has the formula 1 b2 b3 4 b5 6 b7. It is the second mode of Harmonic Minor and differs from Locrian Natural 2 through its lowered 2nd and natural 6th.

The seven modes of Melodic Minor are:

1 — Melodic Minor: 1 2 b3 4 5 6 7;

2 — Dorian b2: 1 b2 b3 4 5 6 b7;

3 — Lydian Augmented: 1 2 3 #4 #5 6 7;

4 — Lydian Dominant: 1 2 3 #4 5 6 b7;

5 — Mixolydian b6: 1 2 3 4 5 b6 b7;

6 — Locrian Natural 2: 1 2 b3 4 b5 b6 b7;

7 — Altered, or Super Locrian: 1 b2 b3 b4 b5 b6 b7.

Over m7b5, begin with the chord tones 1 b3 b5 b7. The diminished 5th identifies the half-diminished quality, while the minor 7th distinguishes it from a fully diminished dim7 chord.

To make the line sound specifically Locrian Natural 2, emphasize the natural 2 through motions such as 1–2–b3, b3–2–1, 2–b3, and b7–1–2, or sustain it as the 9 over the chord. Without it, the melody may sound like an unspecified half-diminished collection or ordinary Locrian without a clearly stated 2nd degree.

The natural 2 lies a whole tone above the root and a semitone below b3. It may resolve upward to the minor 3rd, return downward to the tonic, or function as an independent 9. Unlike the b2 of ordinary Locrian, it does not form a minor 9th against the root.

Degree 4 functions as the 11, while b6 functions as the b13. A minor biii arpeggio supplies b3 b5 b7, the upper three chord tones of m7b5. A major bVII triad supplies b7 2 4, or the b7, 9, and 11 relative to the modal root.

To emphasize the diminished 5th, use motions such as 4–b5, b5–4, and b3–4–b5, together with the arpeggio 1–b3–b5–b7. The natural perfect 5th 5 is absent and changes the quality of the tonic chord.

In an iiø7–V7–i progression, change the target tones with the harmony. Once the progression reaches V7, do not continue mechanically playing Locrian Natural 2: the dominant requires its own major 3rd, minor 7th, and the appropriate altered or natural tensions.

When using the mode as an independent modal center, return regularly to 1, place it in the bass, and use it at phrase endings. Otherwise, the relative Melodic Minor scale rooted on b3 may begin to sound like the more convincing center.

Locrian Natural 2 is the sixth mode of Melodic Minor and a half-diminished scale with the formula 1 2 b3 4 b5 b6 b7. Degrees 1 b3 b5 b7 form an m7b5 chord, while the natural 2 adds the 9 and distinguishes the mode from ordinary Locrian with a b9. Its principal structural degree is b5, while its defining color is the natural 2. Its primary application is over half-diminished chords with a natural 9th, especially iiø7 in a minor iiø7–V7–i progression.