Crash Course

Major keys

For the majority of the time while you’re learning, you can stick to six chords and play the vast majority of songs, in at least a basic form.

Music is just beautiful maths, so there are many aspects of music theory where once you learn something, it applies everywhere, and unlocks loads of new secret levels.

One of these is the six chords.

In any major key, the notes go in a logical order - the alphabet. When they get to G they repeat. So we can easily learn what the notes are in a key.

Let’s use C Major as an example. It’s a good place to start because it has no sharps or flats, and so is basically just white keys on a piano. The first note will be C, and then we just follow the alphabet:

C D E F G A B C

Any major key has six chords which will always work well with each other. In every major key, they follow the pattern:

M m m M M m     (M is Major, m is minor)

So when we apply that to the first six notes of the key of C, we get:

C Dm Em F G Am

So if you already know how to play those chords, then you can compose using any of them in any order. Once you’ve played them all together for a while, you’ll get a feel for what combinations work best.

But what if you don’t know those chords? Well, because it’s all maths, there’s a logic to everything. Remember we’re in the Key of C? Well it’s called a key for a reason. The idea is that the key helps you decrypt the maths.

So let’s look at our notes again:

C D E F G A B C

So all the chords we use in the key of C should contain notes which are in the key of C. Makes sense, right? So how do we figure out which ones?

Well, each chord is made of three notes: Root, Third, Fifth.

The Root is the note which gives the chord its name. You usually play this note at the bottom of the chord.

The Third is the one that controls the mood of the chord. It determines whether the chord is

Major or minor.

The fifth completes the chord.

FUN FACT: Playing only the root and fifth, with no third, is a power chord. The power comes from the fact that without the third, the chord is neither major, nor minor. It's a proto-chord, like a cave-dwelling, club-wielding ancestor of the chord, and it does not mess about. If you want to write a badass metal riff, drop the thirds out of all of your chords.

The names are helpfully logical - to get the notes in a chord, just choose your root, and then take the third and fifth notes along from that:

C D E F G A B C

->

I > C - CEG

II > Dm - DFA

III > Em - EGB

IV > F - FAC

V > G - GBD

VI > A - ACE

The chords are numbered with Roman numerals. This theory applies to all keys. The idea being that if you learn a song in one key and need to change it, you don’t have to re-learn the song in a new key. Just look for the same chord numbers in your new key:

C Am  F   G

I    VI  IV   V

D  Bm  G   A