Video Lesson: All About the 12-Bar Blues Form

THE PROBLEM

You’ve learned the natural minor and minor pentatonic scales, but when you use them in a blues context, they are missing that idiomatic, bluesy sound.

THE SOLUTION

Embark on a study of the blues. Learn the form, the chord changes, the scales, and then start absorbing blues vocabulary by listening and observing how these elements are used in context.

The blues transcends its own genre. You can find it everywhere. Its characteristic 12-bar form and blue notes permeate jazz, rock, country, soul . . . you name it. Even 20th-century composers such as George Gershwin and Igor Stravinsky incorporated blues elements into their work.

The blues is a place where musicians from a wide range of backgrounds and styles can find common ground. It provides a predictable musical backbone, yet allows for countless iterations, variations, and creative liberties. It’s a language with rich and varied dialects—an essential staple of a good vocabulary for any type of musician. In this lesson, we will look at the foundational 12-bar blues form, and then explore the minor blues scale.

Learn the Form

The basic 12-bar blues form is shown in Example 1. Roman numerals are a common way of expressing key-neutral chord changes—the chords will have the same relation to each other, regardless of the key in which they are played. Minor chords are expressed as lowercase Roman numerals, while major chords are expressed with uppercase Roman numerals. The tonic chord—that built on the first scale degree of a key—is indicated as i. Likewise, iv and v are the chords built on scale degrees 4 and 5. In a typical blues, the 12-bar progression is repeated throughout.

Plug in the Chords

Try the 12-bar form with some chords to get it under your fingers and in your ears. Blues has both major and minor modes, and we will start with the guitar-friendly key of E minor. Use your knowledge of scales from previous lessons to spell out the E minor scale, writing scale degrees under each note (Example 2).

Then find the i chord. Go to scale degree 1 to get the root of the chord, and the first part of the chord name, E. Now find the other notes of the chord, by skipping one scale degree up from E to get G, the third. The note G is a minor third above E—the distance of a whole and half step, the same as between the first and third scale degrees of any minor key.

The third determines a chord’s quality—major or minor. The quality of the chord becomes the second part of the chord’s name, so you have E minor. Then skip another scale degree to get the fifth, B. It’s very common in blues to add a seventh, so skip another scale degree from the fifth to get a D. You have spelled out Em7, the seventh chord built on the first scale degree. Use the same procedure for the iv and v chords, and you’ll end up with Am7 (A C E G) and Bm7 (B D F# A), respectively. We will discuss chord construction more thoroughly in a future lesson, so don’t worry if you’re not totally confident on this now.

Now go to the fretboard. There are many ways to play seventh chords across the neck—you can arrange the notes in any configuration your fingers can handle. Start with easy voicings shown in Example 3. Take a moment to get comfortable with the fingerings, then play through the changes using quarter-note strums (Example 4). Once the form is in your ears, try plugging in some moveable voicings that are more common in blues, as shown in Example 5.

Use the Scale

First, play the familiar minor pentatonic over the 12-bar blues form (enlist a friend or use a backing track using a voice memo app on your smartphone). Listen carefully to how each note sounds over each chord. You won’t find any strong dissonances using the pentatonic scale—most notes are melodically “safe” to use over all three chords.

Example 6 shows the minor blues scale, in E minor. It takes the minor pentatonic scale and adds a blue note—the #4 or b5—between the fourth and fifth scale degrees. In the case of E minor, this note is A#/Bb. Try playing it over the blues form. Experiment with using that blue note to create tension and resolution. A hint: The note is often resolved by stepwise motion, going either up to the fifth or down to the fourth. Let your ears guide you. If your guitar has access to the higher frets, you can also try the same scale shape at the 12th fret.

Your next assignment is to take the other pentatonic scales you’ve studied and add the #4/b5. Then try moving between shapes while playing over the blues changes. Finally, try transposing the moveable chords and scale to different keys. As always, let the resulting shapes—and your memorization of them—be an outgrowth of your understanding. Don’t ever check out mentally and lapse into rote finger patterns.

Then do some listening. Listen to B.B. King. Listen to Eric Clapton. Listen to Memphis Minnie, Robert Johnson, Mary Flower, and Derek Trucks. Watch videos of the greats, and absorb the phrasing, the space, the spirit. This lesson is just a place to get some tools and vocabulary to facilitate your journey. But let your heroes and inspirations be your principal guides along the way.

Though you could spend a lifetime becoming fluent in the different dialects of the blues, you’ll also benefit from devoting even a modest amount of time to getting familiar with this incredibly varied idiom. Ride that train as long as suits you. Start by studying the basics, and you’ll be building a strong foundation for greater nuance and vocabulary. It’s well worth it to invest some time in one of the most universal musical languages.