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B♭ in-sen Scale — Guitar Fretboard Visualization

Low E string: F, Ab, Bb, Cb, Eb at frets 1, 4, 6, 7, 11

A string: Bb, Cb, Eb, F, Ab at frets 1, 2, 6, 8, 11

D string: Eb, F, Ab, Bb, Cb at frets 1, 3, 6, 8, 9

G string: Ab, Bb, Cb, Eb, F at frets 1, 3, 4, 8, 10

B string: Cb, Eb, F, Ab, Bb, Cb at frets 0, 4, 6, 9, 11, 12

High E string: F, Ab, Bb, Cb, Eb at frets 1, 4, 6, 7, 11

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Bb in-sen

The in-sen scale is a Japanese pentatonic mixing dark and open colors: root, flat 2nd, 4th, 5th, flat 7th. The flat 2nd supplies the shadow, while the 4th, 5th and flat 7th form the skeleton of a sus chord, so lines resolve into open fourths and fifths. Kenny Kirkland and other jazz players borrowed it for exactly that sus-with-an-edge sound.

it consists of these notes and degrees:

B♭

I

C♭

bII

E♭

IV

F

V

A♭

bVII

Same notes, different mode

Bb in-sen uses the same notes as the scales below. Start from a different note and you get a new mode built on the very same note set.

F locrian pentatonicAb flat three pentatonic

in-sen in all 12 keys, with chords and related scales

tip
  • The dark b2 (B) against an otherwise sus-flavored set (IV, V, b7 (Ab)): open with the half step, then let the 4ths ring.
  • Over a sus7 chord on Bb it behaves like an exotic sus vocabulary; jazz players use exactly this trick.
  • Build riffs in stacked 4ths (b2 (B) to b7 (Ab)... IV to root...); the scale is practically tuned for quartal playing.
  • End phrases on the 5th (F) rather than the root for the traditional floating finish.

How to play B♭ in-sen on guitar

Open B is the one in-scale open string, sitting a minor second over the tonic, which means it colours a phrase rather than anchoring one. Fret 1 on the A string puts a root right by the nut, with the G string root at 3. Lowest root sits at 6 on the low E, so the first box spans frets 6 through 9 before handing to the next at 10. Four flats in the signature.

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