Learning 3rds and 6ths

[Mr. Larry P]

Hi All,

I started learning 3rds and 6ths a while ago then I dropped them because I didn’t really understand what I was doing. So in the last few days I started to study them again and came up with a couple of charts that explains how 3rds and 6ths work. I did the charts only for the G major scale but you can do this for any scale of interest to you.

I hope they help. Enjoy!!

Mr. Larry

[sunjamr]

Nice one, Larry. As for me, I found that you can actually learn the 3rds and 6ths all at once. Just learn to play a scale up and down the neck using the CAGED triad shapes on the upper 3 strings. There are only 3 different shapes, and sequence of the shapes is the same for any key. That way, if you want a 6th, just play strings 1 and 3, or play strings 1 and 2 if you want a 3rd.

Sunjamr Steve

[Mr. Larry P]

Hi Sunjamr,

I understand what you are saying. I don’t see that the sequence of the shapes is the same in any key…not sure how that can be. For example if I go from a G Major to a C major where there is only one note difference F# to F I cannot see how the shape can be the same..

If you get a chance can you explain that in a bit more detail.

Also, I like to do charts to show the notes that are played. It helps me, and I hope others, to become more familiar with the full keyboard. I find that too many explanations offered by others, simply show dots which limit the explanation. Probably just me but I like diagrams laid out with notes not dots.

Mr. Larry

[Jean-Michel G]

The triads that harmonise the G major scale are: G Am Bm C D Em F#°

In the diagram below, these triads are played on the top three strings, starting with the E shape at the third fret.

As I explained in my earlier reply, these shapes are actually first inversions of the G triad, since the bottom note is always the third of the chord.
The notes in yellow for each configuration represent the sixths available in each triad. As you can see, these sixths are either major sixths or minor sixths, but that’s not very important.

The second diagram also represents a harmonised G major scale, but this time the root chord (G) is played in D shape at the 7th fret. All these triads are now second inversions since the bass note is always the fifth of the chord.
Again, the yellow notes are the available sixths. You will notice that their sequence is the same as for the previous diagram, although shifted along the neck.

There is a third way of playing a G triad on the top three strings: an A shape at the 12th fret. However, this is a root position triad (G B D) which does not contain any sixth.

This is why I explained that you only get sixths for inverted triads, never for root position triads.

Diagrams with actual note names tend to be cluttered; also, playing and improvising on a guitar is a very visual activity, where shapes play an important role. Even classical guitarists, when they are sightreading a score, tend to visualise and play intervals more than they read notes.
This is why so many guitar-related diagrams are just dots.
I’m not saying that it is useless to know the names of the notes on the fingerboard, but from a practical perspective it is more important to know how to play all the intervals everywhere on the neck.

[Mr. Larry P]

HI Jean-Michel,

Thank you this is a really good explanation. I’m still in learning mode on 3rds and 6ths so I appreciate the explanation and the diagram.

From the point of view of notes vs dots I tend to learn from note diagrams best which then helps me to remember the patterns. Likely just my way of learning; I can remember numbers and letters for years and names for only a minute or two.

Thanks again, I have printed the diagram and will study it in more detail.

Mr. Larry

[Jean-Michel G]

Steve is right.
In his recent lesson on harmonized 3rds and 6ths, Brian mentions the fact that these intervals live within chord shapes; in fact, more precisely, they live within inversions.

Take a C triad: C = (C E G).
In terms of intervals with respect to the bass note, that’s (Bass 3 5).
The first inversion is C/E = (E G C). In terms of intervals with respect to the bass note, we now have (Bass m3 m6). So here you have an interval of a (minor) sixth.
The second inversion is C/G = (G C E). This is (Bass 4 6); we have another 6th which is now major.

Playing triads on the top three strings actually boils down to playing inversions of each such triad, so 3rds and 6ths come naturally.

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