The Structure of a Chord (triad) for Piano, Keyboard and Organ
There are many types of chords but in this article, we will deal with major triads and minor triads and how to construct them.
First, let us deal with the language used to identify major chords and minor chords. If you are familiar with sheet music and you see a C chord symbol above the staff. All you will see is aCa. This means, play a C major chord with your left hand. If you see a aCma chord symbol. This means play a C minor chord with your left hand. So basically the rules are, you do not need to state that aCa is major or that a triad is major or that a third is major (more on thirds later) but you do need to state that a chord is minor or a triad is minor and so on.
So for example if I want to talk about a C chord, I can say C chord or C major chord (optional). If I want to talk about a C minor chord, I must state C minor. In other words, the major does not need to be stated but the minor must always be stated.
There are twelve major triads and twelve minor triads to learn so by learning one major and one minor you can work out the rest. We will use C chord as our example. Each triad or three note chord consists of a Root a Third and a Fifth. The root for a C chord is aCa the third is aEa and the fifth is aGa. If you are playing on a Keyboard with your left hand aCa is at the bottom (little finger), aEa is in the middle (third finger) and aGa is on top (thumb). So on a keyboard you are playing C chord in root position. It’s called root position because the root aCa (the name of the chord) is the bottom note.
Now let’s look at the distances between notes. The distance from the root to the third is four semitones. The distance from the root to the fifth is seven semitones. These distances apply to all major triads. So if you want to find the notes for G chord. Start with aGa the root then count to the right four semitones from aGa to get aBa (third) and seven semitones from aGa to get aDa(fifth). You have just found G chord (G,B,D).
For minor chords, the only difference is the third. The distance from the root to the third in a major chord is four semitones. The distance from the root to a minor third is three semitones. Therefore, the notes for Cm chord are aCa (root) aEba (minor third) aGa (fifth).
Remember, Major does not have to be stated, it’s optional, but Minor must always be stated.