Topic 6 Major chords

The last aspect that we will consider in this lesson is the representation of some of the most important chords. In music theory, we call a ‘chords’ a specific group of notes identified according to a precise rule. A chord, in its simplest form, consists of three notes that make up a triad. In the case of C major   these three notes are:


It’s very easy to figure out how to locate the three notes that make up a chord. Let’s take our C major scale and number all the notes that form it from 1 to 8:

C, D, E, F, G, A, B, C

1 2 3 4 5 6 7 8

This means that, in order to form the C major chord, we took the first, third and fifth notes of the scale. And this rule applies to the construction of all chords. Use this formula: each chord is identified by the sequence 1-3-5. Be careful, however, to use this sequence always starting from the note on which you want to build the chord. In other words: if we want to understand which notes the F chord is made up of, we will have to refer to the formula 1-3-5 by setting the F as 1. Therefore, in the case of the F chord, the notes will be:

F, A, C

In fact, if we start counting from F (1), the A note will be its third (3) and C its fifth (5). Let’s try the G chord:

G, B, D

Here is a summary scheme for the construction of the triads (we are using the international names for notes on this scheme):

Well, the time has come to give a geometric shape to our chord. All three chords we built (C, F and G) are major chords. What does it mean? The sound of all these chords is probably the most natural that our ear seems to recognize. Usually it arouses a sense of joy and happiness in the listener. If we were to compare it to weather, we would say it sounds like a sunny day. Let’s listen to it. What do you think of it?

Well, let’s move on to building the C major chord in the chromatic circle. Take a rubber band and join the notes of C, E, and G, and you will get this:

As you can see, it is a scalene triangle that has no particular properties (except the one valid for all triangles: the sum of the internal angles is a straight angle) because it is absolutely irregular and, consequently, has no axes of symmetry.

Likewise the intervals between C-E, E-G and G-C are also all different from each other:

  • C-E = 4 sT (2 T)
  • E-G = 3 sT (1 T + 1 sT)
  • G-C = 5 sT (2 T + 1 sT)

Conversely, if we start from a strictly geometric point of view and indicate the vertices of the triangle with letters so that A = Do, B = Mi, C = Sol and proceed clockwise, we could generalize and say that:

Scalene triangle with a shape (2 m – 1.5 m – 2.5 m) = major chord (4 sT) (3 sT) (5 sT)

An even simpler and more immediate indication could be to say that a scalene triangle whose sides respect a proportion of (clockwise) 4-3-5, indicates a major chord.

From a purely musical perspective, the chromatic circle makes it easy to understand which notes make up any major chord. Just rotate the internal disc and set at 12 o’clock the notes which will give the name to the new chords, one after the other. For example, if we want to understand which notes make up the B major chord, we will set the B at twelve o’clock and, reading clockwise, we will read the notes indicated by the vertices of the scalene triangle corresponding to the rule for building major chords. The resulting triad will be: B D# F# (B).