The Blues Scale on Guitar: Adding the Blue Note to Your Pentatonic
The minor pentatonic has five notes. For most rock and pop soloing, that's genuinely enough — you can spend years in those five notes and not run out of things to play. But if you've been wondering what gives blues guitar that particular ache, that tension-and-release quality in SRV's intro to "Pride and Joy" or Clapton's "Crossroads" solo, it comes down to one extra note.
The blues scale is just the minor pentatonic with a flat 5 added. Six notes instead of five. That one addition — called the blue note, the diminished fifth, or the tritone depending on who's teaching — is responsible for most of what we recognize as "the blues sound."
Where the Blue Note Lives in Position 1
If you already know the minor pentatonic in box 1, adding the blues scale takes about thirty seconds to learn. The shape stays almost identical. In the key of A, with your root at the 5th fret on the low E string, your minor pentatonic looks like this:
Low E: 5–8 • A: 5–7 • D: 5–7 • G: 5–7 • B: 5–8 • High E: 5–8
The blues scale adds one fret on the A string: fret 6. So that string becomes 5–6–7 instead of 5–7. That's the Eb, the flat 5 of A. Everything else stays the same.
Physically, it's a squeeze — three notes on one string in a two-fret span. Most players use index finger for fret 5, ring finger for 7, and middle for 6. Some prefer to slide from 5 to 6 and hammer to 7. Either works; the slide-and-hammer approach is actually more blues-idiomatic because that tiny movement — D up to Eb and then E — sounds like a vocal inflection, which is where the blues feel comes from in the first place.
The Blue Note Needs a Destination
Here's what trips most players up: they add the b5 and then run the whole scale up and down like they're doing a drill, and it sounds like a mistake. The blue note isn't a destination — it's a pivot. It creates tension that has to resolve somewhere.
On the A string in key of A, fret 6 (Eb) sits between D (fret 5) and E (fret 7). Almost every blues lick that uses it goes one of two directions: down to D, or up to E. That motion is the whole point. Slide up to Eb from D and immediately resolve to E. Or land on Eb and bend it up to E. Or hammer D–Eb–E in quick succession and let E sustain. The Eb is the word; D or E is the punctuation.
BB King almost never sits on the b5. He touches it on the way to somewhere. Listen to "The Thrill Is Gone" — he uses the blue note constantly, but it's always in motion, always resolving. That's why his phrasing sounds like speech instead of scale-running.
Songs Where You Can Hear It Clearly
Clapton's live "Crossroads" from the Wheels of Fire album (1968) is probably the clearest tutorial that exists for blues scale phrasing. He's in E, working out of box 1 at the 12th fret, and the b5 (Bb on the A string, fret 13) appears in nearly every phrase. Slow it down to 50% on YouTube and watch what happens every time he touches fret 13. It goes somewhere. Every time.
Hendrix's "Red House" is another excellent reference, partly because the tempo is slower and the note separation is cleaner. The opening lick runs up through the pentatonic, touches the b5, and bends from there. Same logic as Crossroads, easier to hear because there's more space between the notes.
SRV's "Pride and Joy" intro uses the blues scale in A so aggressively it's basically a demonstration. He bends the b5 up, he hammers through it, he slides to it from below. If you can name the fret he's on each time in the first 10 seconds, you understand how the scale works.
One thing worth mentioning: Hendrix's "Purple Haze" riff — the famous E5 to Bb5 move — is also a tritone (E to Bb), the same interval as our blue note, just played as a power chord jump rather than a scalar note. Different context but the same edgy sound, and the same instinct to resolve. It goes to A5 immediately.
Moving It to Different Keys
The shape is the same regardless of key. You're just sliding the whole thing up or down the neck. Key of E: start at the 12th fret (or use the open-position version). Key of G: 3rd fret on the low E. Key of D: 10th fret. The b5 always falls one fret above the 4th of the key, on the A string in box 1 — same finger placement, different pitch.
Most beginners learn A first because fret 5 is physically comfortable. Then E. Those two keys cover the majority of blues you'll actually play with other people. G and D come up in country-blues and open-tuning contexts but are less urgent early on.
There's Also a Major Blues Scale
The scale above — minor pentatonic plus b5 — is the minor blues scale. There's a separate major blues scale built on the major pentatonic: 1, 2, b3, 3, 5, 6. The added note is the flat 3, which sits one fret below the major 3rd.
The difference in feel is obvious. Minor blues sounds dark and tense — "Crossroads," "Pride and Joy," "Born Under a Bad Sign." Major blues sounds brighter, almost country-adjacent — "Sweet Home Chicago," "Johnny B. Goode," early Chuck Berry. Both are useful. Most players start with the minor scale, get it into their fingers, then learn the major version as a second vocabulary.
When you can mix them — start a phrase in major blues, dip into the minor b3 for a moment of darkness, resolve back up — that's when improvising starts to feel like actual expression rather than scale navigation. That's months away from where you are now, but it's worth knowing the destination. The improvisation guide covers that next stage in detail.
Where to Go From Here
The immediate goal is simple: add fret 6 on the A string to your pentatonic box 1, and practice using it as a passing note rather than a landing spot. Pick any 12-bar blues in A — the 12-bar structure is worth knowing if you haven't already — and try to use the b5 in at least one phrase per chorus. Just one. Don't force it everywhere.
The instinct to sprinkle it into every lick comes naturally once your ear starts hearing it as tension rather than wrongness. At that point it stops feeling like a scale exercise and starts feeling like vocabulary.