This lesson is going to show you a quick and easy way to find the IV and V chords of a key by using the Circle of Fifths.
The circle as you should already know goes up a Perfect Fifth as you go clockwise around the circle. As you go counter clockwise it goes a Perfect Fourth. In other words the IV and V chord are to the left and right of the root chord.
For Example: If you are in the key of A, your IV chord would be D, and your V chord would be E. Notice that the D is one position counter clockwise to the A, and the E is one position clockwise of the A.
You can use any Dominant chord when you play the 12 Bar Blues. In other words, you can use Dominant 7th, 9th, or 13th chords. In Lesson 25 I concentrated mainly on the Dominant 7th chords, but any Dominant chord will work just fine in the 12 bar blues.