[ssba_hide]Music is mathematics

This is the major scale based on the key of E major:

The roman numeral designations above correspond to the notes in the E major scale. So II-7 or II minor 7 would be F#-7 or F#minor7. Chord progressions written with roman numeral equivalents are used so you can think of the progression in different keys. If we wanted to play Breakfast Blues in the key of C, the II-7 would be D-7 or Dminor7.

If we build basic chords on each step of the E major scale they look like this:

Here’s an analysis of Breakfast Blues:

2 Measure/Bar Intro

|     I7     |  I7  V7 |

12 Measure Progression (12 Bar Blues)

|      I7    |     IV7   |     I7     |V-7 bV7 I7 bI7|   (Bars 1-4)

|     IV7   |IV7(Sus)|  I7  II-7 | III-7 VI7 |     (Bars 5-8)

|     II-7   |     V7    |  I7  VI7  | II-7  V7 |     (Bars 9-12)

7=Dominant 7th, -7=Minor 7th, Sus=Add4