There are seven chords in every diatonic scale – since each of the seven notes in a diatonic scale can become the root of a chord.  We already extracted the first two triads from the first two notes in the C scale, resulting in C major and D minor chords – C and Dmi.  Picking up where we left off, we will extract the remaining five chords, using the every-other-note principle employed in our previous blog.  Here’s E, third note in the C scale:

              1          3             5
C      D      E   F      G      A      B   C

As you can see, E becomes a minor chord just like D did.  So, both the 2nd and 3rd degrees of a major scale are minor chords – in this case Dmi and Emi.

Next let’s do F, the 4th degree of C major:

                  1             3          5
C      D      E   F      G      A      B   C

F results in a major chord just like C did.  So, both C and F are major chords in the key of C.  A better way to think of this: the 1st and 4th degrees of a major scale produce major chords, while the 2nd and 3rd degrees are both minor chords:  C, Dmi, Emi, and F.

Let’s do G, the 5th degree of C major:

                 1             3          5
C    D    E F    G      A      B   C      D

G also results in a major triad, just like C and F did.  So now we have C, Dmi, Emi, F, G.  Let’s do A:

                     1          3             5
C   D   E F   G      A      B   C      D      E

A results in a minor chord, just like D and E did.  So now we have C, Dmi, Emi, F, G, Ami.  Let’s do B:

                         1          3          5
C   D   E F   G   A      B   C      D      E   F

This one is different: we have two minor 3rds joined together.  Remember, a major structure is 2 steps plus 1 1/2 steps (major 3rd and minor third), while the minor chords are the opposite – a minor third followed by a major 3rd.  In the case of B, the 7th degree of C, we get two minor 3rds joined together:  1 1/2 plus 1/1/2.  This chord is called Bmi-5 (B minor flat 5).  Don’t worry about the fancy name – you’ll easily understand it as we get further into chord theory.  For now, just remember the three triad chord structures.

So, in the key of C we have:  C, Dmi, Emi, F, G, Ami, Bmib5 – all seven chords in the key of C.  Again, a better way to think of it is:  the 1st, 4th, and 5th chords are major – the 2nd, 3rd, and 6th chords are minor, and the 7th chord is mib5.  Using roman numerals we get:

I    IImi    IIImi    IV    V    VImi    VIImib5

It all goes back to the structure of the major scale: 1   1   1/2   1   1   1   1/2.  That basic structure is what causes the triad structures:  2+1.5 = major, 1.5+2=minor, 1.5+1.5=minor b5.

Good news – just like our diatonic major structure applies to all keys, the chord pattern in every major key is identical.  In other words, the 1st, 4th, and 5th chords of every key are major – while the 2nd, 3rd, and 6th chords of every key are minor.  And, you guessed it, the 7th chord of every key is minor b5.  All keys share the same identical chord pattern found in the roman numerals above.  Once you know the chords for one key, you know the chords for all keys!  Music is redundant, when you view it as structures rather than individual alpha notes or chords.  Since you know the scales for all 12 keys, and you now know the chord pattern that applies to all of those keys, you now know 84 chords!  (12 x 7).  Actually, it’s even simpler than that, since chords repeat in different positions in different keys, i.e C is the I chord in the key of C – it is also the V chord in the key of F, and the IV chord in the key of G.  Look those up in the chart below.

The most important keys in music – as a practical application, these 8 keys represent 99% of all music you will encounter in your lifetime – in order of most frequent to least, depending on the style of music:

I      II      III      IV      V      VI      VII
D      Emi     F#mi      G      A      Bmi     C#mi-5
G      Ami     Bmi       C      D      Emi     F#mi-5

C      Dmi     Emi       F      G      Ami     Bmi-5

F      Gmi     Ami       Bb     C      Dmi     Emi-5

Bb     Cmi     Dmi       Eb     F      Gmi     Ami-5

Eb     Fmi     Gmi       Ab     Bb     Cmi     Dmi-5

Ab     Bbmi    Cmi       Db     Eb     Fmi     Gmi-5

Db     Ebmi    Fmi       Gb     Ab     Bbmi    Cmib5

The chart above really illustrates the point:  the pattern of chords for all keys is the same.

In summary, we’ve learned to take every other note from a major scale, giving us the root, 3rd, and 5th notes of simple triad chords.  In our next blog, we’re venturing into intermediate level chord concepts – with the introduction of the 7th degree of the chord.  Things are going to start getting pretty exciting – so make certain you really have the concept of triads nailed down tight.  Until then I remain –

Musically yours,

Al