The B blues scale is one of the most useful sounds you can put under your fingers. It's only six notes, it sits comfortably in the middle of the guitar neck, and it gives you that gritty, crying, bent-string sound you've heard in countless blues, rock and soul solos. If you want to start improvising, this is a great place to begin.
Here are the six notes of the B minor blues scale:
B, D, E, F, F#, A
After the A, the scale climbs back to B an octave higher (an octave is the same note name, just higher or lower in pitch) and starts again.
Musicians describe scales with a formula, which numbers each note by its distance from the starting note, called the root. Here the root is B. The formula is:
The "b" just means that note is lowered by one fret compared with the regular major-scale version.
Every scale is a pattern of distances. On guitar these are easy to picture:
The blues scale pattern is W+H - W - H - H - W+H - W. Starting on B, watch it unfold:
You can try this on a single string: play the A string at fret 2 (that's B) and move up 3, 2, 1, 1, 3 and 2 frets. You'll hear the whole scale in a straight line.
Seeing both F and F# in the same scale can look like a mistake. It isn't. The F is the flatted 5th, a 5th lowered by a fret, so it gets the letter name F. The F# is the regular 5th. Two neighbouring notes sharing a letter is perfectly normal in the blues scale, and the spelling tells you exactly what job each note does.
The blues scale is really the B minor pentatonic scale (B, D, E, F#, A), a five-note scale you'll use for life, with one extra note slipped in: the F.
That F is the famous "blue note". On its own it sounds tense, almost wrong. But slide through it, from E up through F to F#, or from F# down through F to E, and it suddenly sounds dark, soulful and expressive. That's the trick: treat F as a passing note or something to lean on briefly, then resolve to E or F#. Hold it too long and it gets uneasy. Pass through it and it's pure blues.
Listen for that little squeeze of tension and release. It's the heart of the sound.
Fun fact: the D major blues scale uses exactly the same six notes. It just treats D as home instead of B, so it sounds brighter.
Some chords are built entirely from notes in this scale, so they blend with it perfectly:
For jamming, the classic choice is a minor blues in B. The standard chords are Bm7, Em7 and F#m7. Not every note of those last two chords is in the scale, but that's fine: the B blues scale is the go-to sound over this progression, and the rub between them is part of the flavour.
A simple 12-bar version, one chord per bar, played in three lines of four bars:
Even simpler: loop Bm7 to Em7, two bars each, and just play.
In standard tuning, you'll find the root B here:
The most popular place to start is the 6th string, fret 7. From there, a comfortable box shape covers frets 7 to 10:
Notice the blue note F appears on the A string at fret 8 and the G string at fret 10. Those are your spicy spots.
Start slowly. Play the box shape up and down until it feels natural, always starting and ending on B. Then put on a Bm7 to Em7 loop and play just three notes, E, F and F#, sliding between them and landing on F#. Once that sounds bluesy to your ears, open up to the full box. Ten relaxed minutes a day will have you making real music faster than you think. Have fun with it.
For the bigger picture, read The Blues Scale (Minor Blues).