Unleashing the Blues: Mastering Dominant 7th Chords on Your Cigar Box Guitar

If you play blues on your cigar box guitar, you must learn several ways of playing a dominant 7th chord. Dominant 7th chords are used in all styles of music, from classical to rock, country to jazz and especially in blues.

Today’s lesson will teach three dominant 7th chords in 10 positions on the 3-string cigar box guitar tuned GDG (G7, C7 and D7). We will also learn three ways to play a 12-bar blues in G using some of the chord voicings you are about to learn. Watch the videos below and play along to help memorize the chord shapes.

Learning many ways to play the same chord (also known as an inversion) is essential when playing rhythm guitar and solos. Most players will learn only a few dominant 7th chords and not explore all the possible voicings. Remember, you can also play the notes of the chords separately, also known as arpeggios.

If you missed the CBG lesson on major chords, go here. If you missed the lesson on minor chords, go here.

First, let’s quickly review the theory behind the dominant 7th chords.

Music Theory – Dominant 7th Chords

Dominant 7th chords are naturally built on the 5th degree of the major scale. When you stack 7th chords from the major key (also known as diatonic 7th chords), you will find only the 5th degree of the scale has a dominant 7th chord. Here are the diatonic 7th chords in the key of C and also on the CBG with the dominant seventh chords in red:

If we take a closer look at the intervals in the dominant 7th we find a major 3rd and two minor 3rds:

Take special notice that the 7th degree of the scale is a flat seventh. This flat seventh is what gives the unique sound of the dominant chord. Another essential element is the chord’s third and flat seventh, creating a flat five interval called the “tritone.” This interval has a unique tendency to want to resolve. You feel satisfied playing a dominant 7th^, followed by the tonic major chord. Play the G7 to C chords below:

We don’t have to go any further with the theory. Just learn to recognize the sound of a dominant chord and the notes that are in it. Alright, time to grab your cigar box guitars and learn some chords.

Learn 10 Ways to Play a G7 on your Cigar Box Guitar

Let’s start with G7, the dominant chord from the key of C major. The notes in a G7 are G-B-D-F. Now, you must realize if you play a 3-string guitar, it’s impossible to play all the notes from the G7 chord! Fortunately, we can hack the chord and just play three of the notes, and everything still sounds fine. This is a common thing to do on the cigar box – the question is, what note can we drop?

If you could choose, the first note to drop would be the 5th of the chord. So, in a G7, we can drop the D. Crazy enough, the second note we can drop is the root note G which gives us a two-note chord or dyad with B and F. Now, this works best if there is a bass or accompanying instrument, but jazz players do this all the time. Particularly, piano players drop notes in the left hand because it is much easier to play three notes instead of four, especially if you are playing fast!

Here is the fretboard showing all the notes of G7 on the 3-string CBG:

Play along with the video and try to memorize the ten different chord shapes:

First, we learned the G7. Next, well will learn the C7 and D7 dominant chords.

10 Ways to Play C7

As you learn the C7 chord, you should start to recognize the same chord shapes from G7. The notes in the C7 chord are C, E, G and Bb. Again, you can drop the G or C and still imply the sound of the C7 chord. 

Here is the fingerboard with all the notes in a C7 on the cigar box:

10 Ways to Play D7

The notes in the D7 chord are D, F#, A and C. The notes you can drop are A and D. Here are all the notes in a D7 chord on the CBG:

Alright, so you have learned how to play ten different dominant 7th chords on your CBG. You have played the video many times and can play all ten chords in under ten seconds, right?

If you have, congratulations!

Let’s learn a few different ways to play the 12-bar blues in G using some of our dominant 7th-chord shapes.

Three Ways to Play a 12-Bar Blues in G on the Cigar Box Guitar

I’m sure most people know what a 12-bar blues is, but here is a quick reminder. The 12-bar blues has 12 bars. Surprise! There are many ways to play the blues, but we will take one of the standard chord progressions and apply our dominant 7th chords.

|G7        | C7       | G7       | G7       |

|C7        | C7       | G7       | G7       |

|D7        | C7       | G7       | D7       |

12-Bar Blues in G #1 

This first 12-bar is probably the most accessible one in the key of G on the cigar box:

12-Bar Blues in G #2 

The following chord progressions combine different voicings to add variety to the standard chords. 

12-Bar Blues in G #3  

The last chord progression will use many chords to give you an idea of how to add more complexity to the 12-bar in G:

Need more blues? Check out some of the other blues lessons on my blog:

Beginner Lesson Learn a 12 Bar Blues

Roots Blues Lesson #1

Roots Blues Lesson #2

Learn the Thrill is Gone by B..B King

Keep Practicing

If you want to go next level cigar box guitar playing, make sure to play through the videos and practice all the chord shapes many times. Study your fingerboard and learn where all the notes are in the GDG tuning.

As many of you will know, there are many more types of chords you can add to the blues and songs you know. Stay tuned in upcoming lessons where we explore more upper structure chords to add spice to your sound.

Good luck; leave any suggestions or comments below for more cigar box guitar lessons. Subscribe to our newsletter or social media channels for more info.

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