If you’ve been following the series of blog posts so far, well done, I guess that means it’s making some sort of sense.

It may seem that these posts are back to front compared to many books. There is a reason for that. I’m not explaining the mechanics of playing an instrument. Books that do this usually start with a few notes or chords to get you going. These posts are more aimed at people who can already play but want to learn more about how music is constructed.

This means I can introduce the scale / major Key system first as I think chords then make more sense because you can see where they fit in.

It also means you’ve done all the hard work already so this is the easy part.

Furthermore, I can then introduce the structure of chords independently of Keys and you can go and work them all out for all keys if you like. This is why introducing intervals then the circle of fifths / fourths first really helps as it’s the foundation for working out any chord you want to.

A chord in essence is basically a group of notes played at the same time. The simplest types of chords are known as triads and contain 3 notes. A major triad contains the root, major third and perfect fifth; A minor triad contains the root, minor third and perfect fifth; A diminished triad contains the root, minor third and diminished fifth.

We can now work out each chord for each of the keys using these formulas and referring to the circle of fifths:

Major – I, III, V
Minor – I, bIII, V
Diminished – I, bIII, bV
So for the key of C we have:
Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin and Bdim
   I           ii           iii        IV      V            vi              vii
Looking at the Circle of Fifths below we can see that these chords comprise of the following notes:
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Cmaj =  C E G
Dmin = D F A
Emin = E G B
Fmaj = F A C
Gmaj = G B D
Amin = A C E
Bdim = B D F
Of course you can use any number of apps to tell you notes in a chord, one I use a lot is Piano Companion by Binitex.  However, the advantage of working them out yourself means that over time you are more likely to remember Keys, the chords in each Key and the notes in each chord which can only help improve your playing.
The 3 most important chords in any Key are the I, IV and V chords.  This is borne out by the fact that many, many songs in different styles use these 3 chords as a basis. You can find songs in classical, pop, folk, country and rock music that use these 3 chords as a basis.
But triads are only the starting point, you can use extended chords which add in additional notes to give your chords more colour and there are many more chord / song structures which can be used.  More on these next time….