To use the blues scale, play the minor pentatonic scale and add the flat 5th, the blue note, as a passing colour over dominant 7th chords. In A, play A, C, D, Eb, E and G over A7, D7 and E7, touching the blue note briefly and landing on the stable notes of the pentatonic scale.
How do you use the blues scale?
The blues scale is used over dominant 7th chords, and the key to using it well is to treat it as a minor pentatonic scale with one extra colour, not as a new scale to learn from scratch. The minor pentatonic scale gives you five safe notes, and the blue note, the flat 5th, gives you one tense note to use sparingly, as a passing colour. In A, play A, C, D, Eb, E and G over A7, D7 and E7, the three chords of a 12-bar blues in A, and the same scale fits all three chords, which is what makes the blues scale so practical. The reason the blues scale works over dominant 7th chords is the clash between the scale and the chords, and that clash is the blues sound. The chords are major triads with a minor 7th, so they have a major 3rd, while the scale has a minor 3rd, and the two 3rds sit a semitone apart, creating a tension that the ear hears as soulful and expressive. The blue note adds another clash, a tritone above the root, which is why it is used as a passing note, touched briefly and moved on from, rather than landed on. The A blues scale shows the notes, and the 12-bar blues progression in A major shows the chords.
How the blues scale fits the chords
In a 12-bar blues the three chords are all dominant 7th chords, and the blues scale of the key fits all three, because each chord shares notes with the scale. In A, the chords are A7, A, C#, E, G, D7, D, F#, A, C, and E7, E, G#, B, D. The A blues scale is A, C, D, Eb, E, G, and it shares the root, 5th and 7th with A7, the root and 5th with D7, and the 5th and 7th with E7. The notes that do not belong to a chord, such as the C against the C# of A7, are the blues notes, and they are the ones that give the music its character. The practical rule is to land on the stable notes and pass through the tense ones. The stable notes of the blues scale are the root, the 4th, the 5th and the minor 7th, which are the notes of the minor pentatonic scale without the minor 3rd. The tense notes are the minor 3rd and the blue note, which should be used as passing notes, approached and left by step, rather than held. Bending is the classic blues technique for the tense notes: bend the minor 3rd up toward the major 3rd, and bend the blue note up toward the 5th, so the tension resolves in the bend itself. The A7 guitar chord and the E7 guitar chord are the chords the scale is played over.
Worked example — a blues lick in E. Play the E blues scale, E, G, A, A#, B, D, over an E7 chord, and try this shape: start on E, move to G, then to A, then touch the blue note, A#, briefly, and land on B, the 5th, which is stable. Then move to D, the minor 7th, and back to E. The blue note is the only tense note in the lick, and it is passed through, not landed on, which is why the lick sounds bluesy rather than wrong. Now try the same shape over A7, the IV chord, and notice that the same notes fit, because the E blues scale shares its notes with the A7 chord. The E blues scale shows the notes, and the E7 guitar chord is the chord it belongs to.
How to practise using the blues scale
Practise the blues scale over a real 12-bar blues, not in isolation, so you learn to hear it against the chords it belongs to.
- Play the 12-bar blues progression in A major slowly, and play the A blues scale over each chord, landing on the root of the chord you are on.
- Practise the blue note as a passing note: play the minor pentatonic scale, add the blue note between the 4th and 5th degrees, and move through it without stopping.
- On guitar, learn the blues scale shape in one position, then bend the blue note up toward the 5th, which is the classic blues technique.
- Improvise over a backing track in E, using only the E blues scale, and aim to land on the root, 5th or minor 7th at the end of each phrase.
- Use the scale finder to find the blues scale for the key you are playing in, and check that its blue note is the flat 5th of the root.
Common mistakes
- Landing on the blue note — The blue note is a passing note, not a resting note. Landing on it and holding it sounds wrong, because it is a tritone above the root. Touch it briefly and move on to a stable note.
- Playing the blues scale over a major 7th chord — The blues scale clashes with the major 7th of a maj7 chord, because the scale's minor 3rd and flat 5th fight the chord's major 7th. The blues scale belongs over dominant 7th chords, not major 7th chords.
- Using only the blues scale — The blues scale is a colour, not a complete language. Mix it with the minor pentatonic scale, the major pentatonic scale and the mixolydian mode, so your playing has more than one sound.
Quick reference
This table shows the three chords of a 12-bar blues in A, with the notes of the A blues scale that fit each chord, so you can see why one scale works over all three chords. The root, 5th and 7th of each chord are in the scale, and the notes that do not belong to a chord are the blues notes, which give the music its character.
| Blues chord | Chord notes | Blues scale notes that fit |
|---|---|---|
| A7 (I7) | A – C# – E – G | A, E, G (root, 5th, 7th) |
| D7 (IV7) | D – F# – A – C | A, C, D (5th, 7th, root) |
| E7 (V7) | E – G# – B – D | E, B, D (root, 5th, 7th) |
Practise the table by playing the A blues scale over each chord in turn, and landing on the notes in the last column at the end of each phrase. When you can hear which notes are stable and which are tense, try the same exercise in E, where the chords are E7, A7 and B7, and the scale is the E blues scale.
Frequently asked questions
How do I use the blues scale?
Play the minor pentatonic scale and add the flat 5th, the blue note, as a passing colour over dominant 7th chords. In A, play A, C, D, Eb, E and G over A7, D7 and E7, touching the blue note briefly and landing on the stable notes.
What chords does the blues scale fit over?
Dominant 7th chords, especially the three chords of a 12-bar blues: the I7, IV7 and V7 chords. The same blues scale fits all three chords, which is what makes it so practical for improvisation.
Should I land on the blue note?
No. The blue note is a passing note, a tritone above the root, and it sounds wrong if you hold it. Touch it briefly, bend it toward the 5th, or slide through it, and land on a stable note such as the root, the 5th or the minor 7th.
Can I use the blues scale in a major key?
Yes, over dominant 7th chords. The blues scale is a minor scale, but it sounds bluesy over major chords in rock and blues, because the clash between the minor 3rd of the scale and the major 3rd of the chord is part of the sound.
How is using the blues scale different from using the minor pentatonic?
One note: the blue note. The minor pentatonic scale has five safe notes, and the blues scale adds the flat 5th as a tense colour. Use the pentatonic notes for stability and the blue note for spice, and the two scales become one tool.