A chord progression is when you have a series of chords in order that are repeated through a piece of music. They often create the structure of the piece.
Below are a number of chord progressions that are related to the blues.
Basic 12-Bar Blues
This is the basic chord progression (pattern) for the traditional Blues.
Each of the Bars ( | | ) last for 4 beats.
| A | A | A | A |
| D | D | A | A |
| E | D | A | E |
Basic 8-Bar Blues
This is the altered blues chord progression (pattern) that was the basis for Rock ‘n’ Roll. There are many variations but this a starting point.
| A | E | A | D |
| A | E | A / D / | A / E / |
Jazz musicians took the 12 – bar blues and the 8 bar blues structures and added more jazz like chords. By using Dominant 7th (A7) chord for every chord will give a Jazzy feel.
The 12-bar would look like this.
| A7 | A7 | A7 | A7 |
| D7 | D7 | A7 | A7 |
| E7 | D7 | A7 | E7 |
The 8-bar would look like this.
| A7 | E7 | A7 | D7 |
| A7 | E7 | A7 / D7 / | A7 / E7 / |
Below are examples of the chord shapes mentioned in the chord progressions above.