The Blues Scale on Guitar: One Note That Changes Everything

The blues scale is the minor pentatonic with one extra note, the flat fifth. Its formula is 1, ♭3, 4, ♭5, 5, ♭7; in A that's A, C, D, E♭, E and G. The added note, often called the blue note, works best as a passing note between the fourth and fifth rather than somewhere to stop.

The blues scale formula

Measured from the root, the blues scale is:

• Root (A) — home.
• Flat third (C) — three frets up; the minor sound.
• Fourth (D) — five frets up.
• Flat fifth (E♭) — six frets up, exactly half an octave. This is the blue note.
• Fifth (E) — seven frets up.
• Flat seventh (G) — ten frets up.

That gives it six notes rather than five, and something no pentatonic scale has: three notes in a row a semitone apart, D, E♭ and E. That chromatic squeeze is the sound people mean when they say a line sounds bluesy. It's part of the pentatonic lessons, because it's built directly on the pentatonic scale.

Minor pentatonic vs blues scale

The two are one note apart. The minor pentatonic is 1, ♭3, 4, 5,♭7; the blues scale adds the ♭5. So every pentatonic shape you know is already a blues scale with one note missing, and you don't need new positions, just the extra fret in each.

The difference in sound is about tension. The pentatonic has no semitones, so nothing in it rubs. The flat fifth adds a semitone on either side, which gives lines a grinding, unresolved quality. Used for a moment, it's expressive; held for a beat, it can sound like a wrong note. Most players treat the blues scale as the pentatonic with a spice they add when they want it.

The blue note in all five positions

Here are the five A minor pentatonic positions with every E♭ inside each one's fret span added, outlined. Some positions have the blue note on two or three strings, some on only one; that's simply where E♭ falls in standard tuning.

In position 1, the two blue notes — the 6th fret of the A string and the 8th fret of the G string — are the ones you'll use most. Each sits one fret above a fourth (D) you already play in the box, which is exactly where the note is meant to be used: on the way from the fourth up to the fifth.

Use the flat fifth as a passing note

The blue note sounds best on the move. The classic uses:

• Climbing: fourth to flat fifth to fifth (D, E♭, E), landing on the fifth.
• Falling: fifth to flat fifth to fourth (E, E♭, D), often continuing down to the flat third.
• Turning: fourth, flat fifth, back to the fourth (D, E♭, D) — a small wobble around the note.
• Bending: bend the fourth up a half step to the flat fifth, or a whole step to the fifth, passing through the blue note on the way.

In every case the E♭ is there for a fraction of a beat, and the phrase lands on a stronger note straight after. If you hold it, make it a deliberate moment of tension and resolve it soon afterwards.

Three blues licks in A

All three sit around position 1, at the 5th fret. Play them slowly over an A drone or a blues backing track, and let the final note ring.

1. The chromatic climb

A string 5th fret (D), 6th fret (E♭), 7th fret (E), then the D string 7th fret (A). Four notes that walk up through the blue note and resolve on the root.

2. The turnaround wobble

G string 7th fret (D), 8th fret (E♭), back to the 7th (D), down to the 5th (C), then the D string 7th fret (A). The blue note becomes a small twist in the middle of a falling line.

3. The long descent

High e 8th fret (C), 5th fret (A); B string 8th fret (G), 5th fret (E); G string 8th fret (E♭), 7th fret (D), 5th fret (C); then the D string 7th fret (A). It works down through the whole position, using the blue note once on the way.

Over a 12-bar blues

In a 12-bar blues in A, the chords are A7, D7 and E7. The A blues scale works over all three, but the blue note behaves differently over each. Over A7 it's the classic tension against the chord. Over D7 it's a semitone above the root, and over E7 a semitone below it, so on those two chords it clashes if you hold it. Keep it moving there, and save the long, bent blue notes for the A7 bars.

As the chords change, aim each phrase at a note of the new chord, as in soloing over chord changes. The blues scale gives you the attitude; the chord tones give you direction.

The major blues scale

There's a major version too: 1, 2, ♭3, 3, 5, 6. In A that's A, B, C, C♯, E and F♯. It's the major pentatonic with a flat third added, and the move from C to C♯ — flat third sliding up to the major third — is one of the most recognisable sounds in country and blues-rock.

Just as the major and minor pentatonic share notes, A major blues uses exactly the same notes as F♯ blues, three frets lower. So the minor blues shapes, started from F♯, give you A major blues.

Common mistakes

Landing on the blue note

Ending a phrase on E♭ leaves it hanging. Unless you want that tension on purpose, move through it and stop on the fourth, fifth or root.

Using it in every phrase

The blue note works because it's a surprise. Put it in every lick and it stops sounding special. Use the plain pentatonic most of the time and add the flat fifth when a phrase needs an edge.

Forgetting the chords

The same note can sound great over A7 and rough over D7 or E7. Listen to which chord is underneath before you lean on it.

A practice routine

Ten to fifteen minutes a day, in A.

1. Week 1 — position 1 with the blue note. Play the position 1 box adding the A-string and G-string E♭s. Then play the three passing-note moves on each.
2. Week 2 — the licks. Learn the three licks, then change one note in each to make your own version.
3. Week 3 — over a 12-bar. Improvise in position 1 over a slow 12-bar in A, using the blue note mostly over the A7 bars.
4. Week 4 — other positions. Find the blue note in positions 2 and 3, and connect them to position 1 through the pentatonic notes they share.