Blues

The notes

B♭ D♭ E♭ E F A♭, then B♭ — writing the flat fifth as E natural for readability, though it functions as F♭. The E is the blue note and is played through rather than held.

The scale works over B♭7, E♭7 and F7 alike, which is what allows blues improvisation to ignore the chord changes and follow the phrase instead.

On the fretboard

Sixth fret with the root on the low E string — the same box as every other blues scale, moved. That portability is the whole method: learn the shape once, and the key becomes a matter of position.

Because nothing is open, every note bends. In E or A the tonic is an open string and cannot be bent up to; here it can, which changes how phrases end.

Where it is used

Jazz blues and jam sessions with horns, where B♭ and F are the default keys. A guitarist who knows only the E and A boxes will be lost in that room.

It also appears in soul and funk, which inherited their key preferences from the horn sections that recorded them.

Learning this position is also the cheapest way to sound prepared. Horn players call keys by their own convenience, and a guitarist who can move the box to the sixth fret without thinking has removed the only real obstacle to playing with them.