I have a confession. It's really embarrassing.
I have been playing the piano since I was nine-years-old, and I only learned what diatonic chords are THIS YEAR! But I figured if this happened to me, then it could happen to you. I don't want that to be the case because diatonic chords are AMAZING and so very useful!!
So this lesson is for all of you who don't yet know what a diatonic chord is!
What Is A Diatonic Chord?
Diatonic chords are super simple. They are just the chords that naturally occur within a certain key signature or scale. It's easiest to understand this by thinking of the C scale.
In the key of C, we have all white notes. So the diatonic chords in C will have all white notes.
Let's start at C and work our way up. Our C chord has the notes C-E-G. So it's a C Major chord. Easy, right?
Next, we move up to D. Our D chord has the notes D-F-A. Now there are no black keys in C, so it's a D minor chord. So D minor is a diatonic chord of C. Make sense?
The next note is E. The E chord is E-G-B. Another minor chord, because we are only using white notes. So E minor is also a diatonic chord of C.
Up to F and we have F-A-C. F Major.
G is G-B-D, making G Major
A is A-C-E, so it's another minor chord. A minor.
B is where things get a bit 'crunchy'. Because we have only white keys our B chord looks like this: B-D-F. It's not B Major (B-D#-F#) and it's not B minor (B-D-F#). It's actually B diminished. This is a characteristic of diatonic chords. Every 7th diatonic chord in a Major key will be diminished.
So to recap. All the diatonic chords in the key of C are:
C, Dm, Em, F, G, Am, Bdim and back up to C at the top.
So there's a pattern here. The 1-4-5 chords are all Major chords. The 2-3-6 are all minor chords, and the 7 is a diminished chord.
C is an easy key to see this in, but to really learn it we should try it out in other keys. Let's look at the key of D.
Now D has two sharps. F# and C#. So that means any chord containing an F or a C will have to make it F# and C#.
So we have: D, Em, F#m, G, A, Bm, C#dim (because it's the 7), D.
Up until now, we've looked at the theory behind diatonic chords. So why is it important to know?
It's important because learning the diatonic chords of a variety of keys will help you to become familiar with chords that go together as well as provide you with a really fun way to train your ear and get comfortable playing in a variety of keys.
Knowing the diatonic chords of any given key will also help you to create your own unique chord progressions, analyze music, play songs by ear, and give you a head start when it comes to guessing what chords will show up in your favorite songs.
The Next Steps
So now you know what diatonic chords are, it's time to practice and learn them in different key signatures! Try choosing a new key signature each day and learning the diatonic chords of that key. It will really help you to learn the keys better and faster, and it will also help you when you need to transpose music, because you can look at the patterns of the chords and you'll already know what they are in any given key!
So try it out, and good luck!