C# Chord Progressions: iii and III Substitutions

Db and C# are essentially the same key, as they contain the same notes, but with different names. Those keys are called enharmonic:

I. C# major
ii. D#m
iii. E#m (we'll refer to this as Fm for simplicity's sake)
IV. F# major
V. G# major
vi. A#m
vii(b5). B#dim (we'll refer to this as Cdim for simplicity's sake)

The C# major diatonic scale is as follows: C# D# E# F# G# A# B# C# (again, E# is better known as F, and B# is better known as C)

Therefore, the relative minor of C# major (the chord and the scale) is A# minor.

The A# natural minor scale is as follows: A# B# C# D# E# F# G# A# (compare with C# major).

The A# harmonic minor scale is as follows: A# B# C# D# E# F# G## A# (note the singular difference between the natural and harmonic minor scales, and that G## is usually referred to as the A note).

Now we have those ground rules established, it might help in the songwriting process to substitute the mellow iii chord with a more confident III chord. Going back to the simple relative minor substitutions from last time, let's try the following progression:

I-V-I-V-IV-V-I (I-V): C# G# C# G# F# G# C# (play C# G# quickly)

Let's replace some I and V chords with their relative minors, vi and iii respectively.

I-V-vi-iii-IV-V-I (vi-V): C# G# A#m Fm F# G# C# (A#m G#)

Let's replace the iii chord with a III chord (that is a major chord).

I-V-vi-III-IV-V-I (vi-V): C# G# A#m F F# G# C# (A#m G#)

Anyway, to connect with the natural minor and harmonic minor scales mentioned above, let's look at the iii and III chords.

iii. F minor chord (F G# C notes)

III. F major chord (F A C notes)