Chord Theory – An Essential Guide To Understanding Chords

Minor Sixth Chord Theory

Pro Tip: Here’s a piece of chord theory I wish someone had told me earlier on in my musical career, which would have saved me quite a few wrong-sounding chords.

The “minor” in a minor sixth chord refers to the third, not the sixth.

So a Cm6 chord is spelled 1, b3, 5, 6. If you look at the C major scale, that’s C, Eb, G, A.

Here are some moveable sixth and minor sixth chord shapes for you to try:


Seventh Chord Theory

Okay, so if all sixth chords are spelled 1, 3, 5, 6, then all seventh chords are spelled 1, 3, 5, 7, right?

Not quite.

It’s true that one kind of seventh chord is spelled 1, 3, 5, 7, but there are a few different kinds of seventh chords, and they all have their own qualities.

By the time you get done reading this, you will be a chord theory expert in the most common kinds of seventh chords and their spelling.


Major Seventh Chord Theory (maj7)

The major seventh chord sounds smooth, peaceful, and pretty. You can hear it all over the place in this lovely old song, “Ventura Highway” by America.

The major seventh chord is spelled 1, 3, 5, 7. That’s a major chord with a major seventh added.

An Fmaj7, for example, has the F major chord – F, A, C – and also an E.

Check out this lesson on the Fmaj7 Chord – 5 Ways to Play this Lovely Chord to dig a little deeper!

Here are some major seventh chord shapes for you to try:


Minor Seventh Chord Theory (m7, min7, -7)

Minor seventh chords sound like minor chords with the pointy edges sanded off.

They are very mellow sounding..

Here’s Neil Young with “Cortez the Killer” to show you how to use an Em7 and an Am7, the first and third chords in the song.

As with all major and minor chords, the root and the fifth notes of the chord stay the same, and the action takes place in the third and seventh.

  • A minor seventh chord is spelled 1, b3, 5, b7. It is a minor chord with a minor seventh added.
  • An Em7 is E, G, B with a D added.
  • Where you add the minor seventh can affect the personality of the chord.

Take a look at these two voicings:

Em7 (020000) and (022030)

  • The first voicing buries the D (the fourth note) in the middle of the chord.
  • The second voicing puts the D near the top of the chord so you can hear it more prominently against the open E string.


Download our lead guitar cheat-sheet to make things easier

It can be disorientating for guitarists to understand which scales work with which keys.

With this in mind, we created a cheat-sheet; a key and scale-finder that you can use again and again.

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Dominant Seventh Chord Theory

The dominant seventh chord is a mix of major and minor, and for that reason, it’s most commonly characterized as “bluesy.”

  • Here’s a little “Sweet Home Chicago” to illustrate the point. All dominant seventh chords!
  • The dominant seventh chord is spelled 1, 3, 5, b7. That’s a major chord with a minor seventh added.

There are a lot of ways to make a dominant seventh chord happen on the guitar.

Here’s a sample:

Other Slightly Less Common Seventh Chords

If you’ve gotten used to using the scale chart and the spelling method to figure out some of the chords above, you’ve mastered a huge part of chord theory!

The numbers, flat and sharp signs in all chords simply reflect instructions about what notes to add to a major or minor chord.

  • Em(maj7), called a minor-major seventh chord, is an E minor chord with a major seventh added. It’s spelled 1, b3, 5, 7 (or E, G, B, D#).
  • The minor-major seventh chord is the second chord in “Blue Skies” by Willie Nelson.
  • Em7b5, called a minor seventh flat five, is an E minor chord with a minor seventh added and the fifth flatted. It’s spelled 1, b3, b5, b7, or E, G, Bb, D.

To dig a little deeper into chord theory, check out this excellent guitar chord theory book!

Pro-Tip: You have probably seen numbers that do not exist on our handy scale chart attached to chords.

That’s a topic for a different lesson, but the short answer to that is in chord theory, you find those notes by extending the scale, so that a 9 is the same note as a 2, an 11 is the same as a 4, and a 13 is the same as a 6.

Mapping Chord Theory on the Fretboard

Chord theory is fascinating!

It’s a great intellectual exercise for sure – but to really understand how chords work, the wisest use of your time is to print out some fretboard charts and start mapping out chords.

You can find yourself some interesting shapes, and even figure out your own ways to change between chords!

Recommended Resources

If you enjoyed this lesson on chord theory, you’ll certainly love these other free guitar lessons we have for you below:

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