Having reached the key of Cb with all seven note flatted you
could be forgiven for thinking that you have come to the end
of the circle. But if that was the case it wouldn’t be
called a circle as, by definition, circles don’t have
So let’s continue applying the rules:
From Cb we go up four steps:
Cb Db Eb Fb
So the next key in the circle of fifths is Fb major.
Fb Gb Ab Bb Cb Db Eb Fb
The rules say we should now add a flat to the 4th note and
we can see that this is necessary to maintain the major scale
Fb [T] Gb [T] Ab [S] Bbb
[T] Cb [T] Db [T] Eb [S] Fb
Bbb sounds the same as A but we can’t call that note
A in a key where we already have an Ab.
Now you might complain that you have never seen a piece of
music written in a key with double flats (they do exist,
but are exceedingly rare). Later on we’ll discover exactly
why this is.
However, even if you never play in these keys,
it is important to understand the concept because, if you go
on to study harmonizing (which is probably the most interesting
and useful section of music theory for guitar players), you
will need to be able to carry out theory work in all keys,
including those with double flats.
The next key in the circle is:
Fb Gb Ab Bbb
The key of Bbb major.
It has 9 bs :
Bbb Cb Db Ebb
Fb Gb Ab Bbb
Then up four to Ebb major with its 10 bs:
Ebb Fb Gb Abb Bbb Cb Db Ebb
And up another five steps to Abb major with 11 bs:
Abb Bbb Cb Dbb Ebb Fb Gb Abb
And finally we might imagine that the next key would be Dbb
Dbb Ebb Fb Gbb Abb Bbb Cb Dbb
But if we look closely we can see that:
Dbb =C, Ebb =D, Fb = E,
Gbb =F, Abb =G, Bbb =A,
Cb =B, and Dbb =C
So we are now truly back at the start of the circle in the
key of C major which has no flats.
C D E F G A B C
So that’s the circle of fourths, but, for every key
with flats in the key signature there is one that sounds the
same, but uses sharps instead of flats. You can read all about
sharp keys in the circle of fifths.
If you have already sorted the circle of fifths out then
take a look at the second part of the Key
signatures page where we bring all this magical stuff
together so that it (hopefully) makes sense!