One of the first chord progressions we learn as guitarists is the 12 bar blues progression. If you're in the key of E, you'll find an A chord and a B7 in the series. We all get to recognize this sound quite quickly. The changes become very familiar and easy to hear.
|"This ability to hear the changes is of utmost importance if you want to be able to improvise."|
This 12 bar progression uses the three major chords found in any key, the I, IV and V chords. There are also three minor chords in any key ( II, III, and VI ) and, the fly in the ointment, a half diminished chord, the VII chord. These seven chords arise out of the major scale and are related to each other like members of a family.
Get to hear these other chords as easily as you hear the 12 bar chords. Train your ear to recognize the changes. The VI chord ( also called the relative minor ) is probably the easiest to
hear. The other two minors ( II and III ) are a little harder to lock onto. Don't worry too much about the VII chord, the half diminished. It doesn't come up very often. I prefer to view it as another V chord.
This ability to hear the changes is of utmost importance if you want to be able to improvise. The chord of the moment sets the rules, so its very important to know what it is.