Major keys are the cornerstone of most musical composition. Even seemingly unrelated keys, like minor keys, can be thought of as variations of the major key system. Knowing how to build a major key from scratch is an important first step to understanding music theory.

What the heck is a key?

Let’s begin by defining what a key is. The way I like to describe it to my students is a key is a collection of seven notes that sound particularly good together. Western music, that is music we’re accustomed to hearing in most parts of Europe, and the Americas, has 12 notes total, spread across many octaves. When we remove five of the less appealing notes and leave behind seven notes that sound lovely together, we have a key. Think of a key as a shortcut to the notes that are guaranteed to sound good together.

Where to begin?

The most important thing to know when building a key is which note you’d like to start with. You can start from any note. Whichever note you choose will be the namesake of the key. If you start on Bb, you’re building the key of Bb. Start on F#, you’re building the key of F#. For know, we’ll start with the key of C.

Knowing which notes to skip.

Okay, we have our starting point: C. What’s next? Right now, if we start on C and play every note we can until we arrive at another C an octave higher, we’ll play 12 notes, known as the chromatic scale:

C  C#  D  D#  E  F  F#  G  G#  A  A#  B  C

It won’t sound very musical. Take a listen:

To avoid that, we have to decide which five notes to skip.  That’s a tough call! How do we decide!? Luckily, the process isn’t arbitrary. All major keys have something in common: the five instances where we skip a note always occurs in the same place.

You see, all major scales follow a pattern of movements from one note to the next:

Whole Step – Whole Step – Half Step – Whole Step – Whole Step – Whole Step – Half Step

or

w w h w w w h for short.

If you’re not sure what whole steps or half steps are, check this article out.

Let’s build the key of C using the major key interval pattern.

C + w = D + w = E + h = F + w = G + w = A + w = B + h = C

Here’s another way to look at it:

The dimmed notes are the five notes that we skipped. You see, every time we use a whole step, we’re skipping a note. That’s how we decide which notes don’t belong. We simply follow the major key interval pattern. Now that the less desirable notes have been removed, here’s what our major key sounds like:

Let’s try it with a different starting note. We’ll start with D, thus building the key of D.

To summarize, what we’ve done is start with a note from which we’d like to build a key. Then we write out the twelve notes chromatic scale, plus the octave of our key. Lastly, we use the major key interval pattern to eliminate five notes, leaving behind the seven notes that make up the key. That’s it!

For more information about me and the guitar lessons that I give in and around Baltimore, visit www.ewguitar.com.