Triads, why are they so important?

There is a common scenario in many bands with two guitars where both guitars are playing exactly the same chords at some point in the song. In these situations, in my opinion, it's best to stop playing until the next section unless you know how to use triads. There is a maxim that says:”the bigger the band, the less you play”. In other words, “play less but better”.

There are other situations, like a band with an organ or keyboard player comping with chords that take up a lot of harmonic space. In this case, other chord instruments such as guitar must find their own spot if they want to deal with whatever the other players are laying down.

To find your own harmonic space using chords on guitar — or any other chord instrument — triads will do the trick. Triads use only three notes: generally, these are the root, the third, and the fifth, and are played on adjacent strings in groups of three. Imagine a chord progression where the rhythm guitar is playing open chords or barre chords using all the strings at the same time, like the following:

Or the same chord progression using only barre chords:

As you can see in this common I / IV / I / V chord progression, the guitar is using all the strings, so some notes are repeated. These repetitions work well when a guitar is strummed or arpeggiated. The more notes a chord has, the bigger its sound will be. So if you are a single player or the main rhythm guitar, don’t worry about these chords — but if you are trying to arrange a second guitar, please forget them unless you have a good reason for using them.

Composing a second guitar part or creating a guitar arrangement is where triads make sense. Triads are one of the cornerstones of guitar composition and one of the first things anyone who wants to speak through their guitar should learn.

Following the chord progression above, we're going to demonstrate how to figure out which triads can be used.

The first thing is to identify our chords on the whole neck using the CAGED system. Our first chord is a CMaj and is played using the C shape so following the CAGED we know that the next chord will have the A shape and so on.

These are the CAGED chords for our chord progression:

Once we’ve identified our CAGED shapes, we can extract the triads from them. As we’ve said before, these shapes have repeated notes, but we only want to use the 1st, 3rd and 5th.

So, for example, assuming the C Maj chord in A shape is our first position, we can extract these triads from it:

As you can see, triads are grouped by string sets. Using E and C shapes we can extract the rest of triad shapes for the 1st set of strings (from 1st to 3rd string) and for the 2nd set of strings (from 2nd to 4th string):

With these three CAGED shapes, we've been able to figure out all the major triads from the first to the fourth string. With the C, G, and D shapes we'll be able to extract the ones for the lower notes. Now you know where triads come from and what the theory behind them is. In the next articles, we'll take a look at other common progressions using triads and which shapes are used for the minor, diminished, and dominant seventh triads. Remember, understanding triads is essential if you want to arrange, improvise, or compose on guitar.