How to Play the Blues Scale on the Guitar
You can’t talk about blues on the guitar without mentioning the so-called blues scale, which is really just a pentatonic scale with a chromatic passing tone. This added scale tone is a f5th in the minor pentatonic. When the pattern is applied as major, the same note in the patterns becomes a f3rd.
Here is an example that includes A minor pentatonic patterns with added f5ths shown in gray.
You can see an example in Playing the Blues Scale.
You don’t have to memorize and practice all these blues scale patterns, but you should at least try them all and commit the first one to memory. That way, as you work through songs with blues elements in them, you’ll be able to make sense of any f5ths you see.
Because C is the relative major to A minor, you use the same notes and patterns to play C major pentatonic that you use to play A minor pentatonic. The only difference is which note functions as the tonic and counts as the 1st scale degree.
Here are the same patterns redrawn with the C notes marked as 1. Everything has been renumbered from there. So what was a f5th in the A minor blues scale becomes a f3rd in the C major blues scale.
You can transpose blues scale patterns to play blues scales in other keys. For instance, if you want to play a minor blues scale for a particular note on the 6th string, put your 1st finger on it and play the 1st pattern. If you want to play a major blues scale for a note on the 6th string, put your 4th finger on it and play the 1st pattern.
Putting your 4th finger on a note means that you actually start the 1st pattern three frets lower with your 1st finger. For example, the 1st A minor blues scale pattern starts at the 5th fret with the 1st finger. The 1st A major blues scale pattern starts at the 2nd fret with the 1st finger, putting your 4th finger at the 5th fret on A.
Songs that make use of the major or minor blues scale at some point include the following:
Black Dog by Led Zeppelin
The Devil Went Down to Georgia by the Charlie Daniels Band
Heartbreaker by Led Zeppelin
Love Her Madly by The Doors
The Old Man Down the Road by John Fogerty
Pride and Joy by Stevie Ray Vaughan
Roadhouse Blues by The Doors
Rock and Roll, Hoochie Koo by Rick Derringer
Sir Duke by Stevie Wonder
Sunshine of Your Love by Cream
Take It Easy by the Eagles
Truckin’ by Grateful Dead
Some songs, like Black Dog by Led Zeppelin and Manic Depression by Jimi Hendrix, make use of an additional chromatic passing tone in the pentatonic scale. Specifically, they add a chromatic step in between f7 and 1 in the minor pentatonic, as shown here.
Whenever you’re applying the pentatonic scale, whether it’s major or minor and whether you’re using it on a blues song or something else, you can always try using chromatic passing tones. If they sound good to your ears, go with them. If they don’t, skip them.
Blues music often features chromatic passing tones. Whenever you come across a run of three or more notes in consecutive frets, you’re probably just connecting pentatonic scale tones with chromatics.