[ Triads ]
There are many different ways of figuring out what key a particular song is in - one of them is by analyzing the chord change.
If we know what key a chord change is in, then we can find the appropriate scale to solo with. We will also know which chords are OUT of key and adjust our scales accordingly.
If you haven't already done so, it would be a good idea to read through the Basic Chord Theory before working through this section.
The formula for the chords in key is
M m m M M m o M = chord quality 1 2 3 4 5 6 7 1 = chord degree
[ M = major , m = minor, o = diminished triad ]
The condensed version:
1M 2m 3m 4M 5M 6m 7o
We apply this formula to the major scale.
Let's
take "C" major, for example:
C D E F G A B C = note name 1 2 3 4 5 6 7 8 = note degree
Then we mix the two together -
CM Dm Em FM GM Am Bo CM 1 2 3 4 5 6 7 8
We take the major scale and then make chords out of each note of the scale. The C note becomes a C major chord (C or CM), the D note becomes a D minor chord (Dm), the E note becomes an E minor chord (Em) and so on until we cover the 7 different notes of the major scale.
You've might of heard the expression, play a 2-5-1 progression or 1-6-4-5
chord change.
These numbers usually refer to the chords in key.
A 2-5-1
in the key of C is Dm G C
A 1-6-2-5 in the key of C is C Am Dm G
Let's find the chords of another key, how about E ?
What's the major scale?
You should have E F# G# A B C# D# E .
What's the chords in key formula ?
You should have M m m M M m o M
Now put the two together to get:
E F#m G#m A B C#m D#o E
These are
the ONLY basic chords (triads) that can belong to the key of E!
Any other
triad is NOT in the key of E.
It is common to see chord numbers written out with Roman Numerals.
A
standard way of writing out the chords in key is:
I IIm IIIm IV V VIm VIIo
Some people use lower case for minor chords:
I ii iii IV V vi vii
but
it doesn't work for the vii which is a diminished chord.
What would be a IIm-V-I in the key of D?
D major = D E F# G A B C# D
1 2 3 4 5 6 7 1
E is II. A is V. D is I
Em - A - D is the IIm-V-I in the key of D.
What would be a I-VIm-IV-V in the key of F?
F major = F G A Bb C D E F
1 2 3 4 5 6 7 1
F is I. D is VI. Bb is IV. C is V.
F - Dm - Bb - C is the I-VIm-IV-V
in the key of F.
Try to answer the questions about major keys in the Chords in Key Quiz #1 - Triads .
Now we're ready to start looking at chord changes and find out what key they are in by recognizing chord patterns.
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