I7-ii7-iii7 Progression- Part Two

Let’s take a closer look at the I7-ii7-iii7 progression.

​I7-ii7-iii7 is nothing more than I-V-I because:

• ii substitutes for the V7 chord.
• iii substitutes for the I7 chord. 

​How does the ii chord substitute for the V chord? The ii (Dm) chord shares two common tones with the V7 (G7) chord. What are they?

• The root of ii (D) is the 5th of V.

The 3rd of ii (F) is the dominant 7th of V.

​Dm6 (inversion)        ii Chord

G7   V7 Chord

​How does the iii chord substitute for the I chord? The iii chord is a 1maj7 chord. It is the exact same chord less the root. 

​Em7     iii Chord

CMaj7     I7 Chord