What Is a Chord?

A chord is defined as three or more notes played simultaneously. But which three? Any three notes? Understanding where chords come from will help you get a thorough grasp on them. Guitarists commonly think of chords as “grips,” “boxes,” or “shapes.” This thinking is convenient to understanding guitar playing, but to understand music, you should know how chords evolved.

In the Old Days …

Originally, music was written one line at a time, usually for singers or small instrumental groups. When music evolved to have more than one line sung or played at the same time, people found that certain notes sounded good together, and other notes didn't. As a result, rules were created that stated what intervals could be played together—certain intervals like thirds, fifths, and sixths sounded good together, while other intervals did not. As music evolved into more than two lines played together, certain groupings of notes were commonly found to sound good together. The composers didn't think of chords at this time; what they did think about were individual lines of melody that intersected to form what we know today as chords. If you look back on this old music you can see things that resembled chords. It wasn't until Jean-Philippe Rameau theorized about chords in the eighteenth century that chords were named and understood. But as with all theory, Rameau spoke about chords after they happened, so all he did was name something that already existed.

Triads

Rameau spoke of groupings of notes called triads, which are three-note chords, built in the intervals of thirds. He theorized that triads are formed by stacking or “harmonizing” a major scale together. What he thought in 1722 still holds true today, even in rock and blues music. Chords and harmony come from a harmonized major scale. Let's look at the harmonized C-Major scale in FIGURE 8-1 to see how triads are formed.

As you can see from the music, these chords are formed by taking notes of the C-Major scale and combining them with other notes from the scale. The method for forming triads is very simple, and if you can draw a major scale, either in music or in letters, you can form triads. Here's an example in letters for you to see how the scale is formed:

STEP 1 Write a C-Major scale on a piece of paper.

C D E F G A B C

STEP 2 Add the interval of a third above each of the notes in the C-Major scale. That is, write E above C, F above D, and so on:

E F G A B C D E

C D E F G A B C

STEP 3 Place thirds again above the line of notes that starts with E. Using notes from the C-Major scale, write G above E, A above F, and so on:

G A B C D E F G

E F G A B C D E

C D E F G A B C

You just formed chords. (Read the chords from bottom to top on vertical rows.) Let's look at the harmonized scale in FIGURE 8-2, but this time with the names of the chords.

Just by simply arranging the scale in that order you were able to make a lot of chords. Look at the first C-Major chord in FIGURE 8-3.

Now as you look at the music and tab, you might say, “That's not the C-Major chord I play.” You could be used to playing any of the C-Major chords in FIGURE 8-4.

Every one of these chords is a C-Major because each one contains the notes C, E, and G. Some chord shapes, or voicings, contain repeats of the three original notes. But under no circumstances will a C-Major chord ever contain more than three discrete pitches. When you harmonize the scale, you get the basic information about what notes the chords contain, but you won't get chord shapes that look familiar.

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