In its basic Jazz form, Blues consists of three chord changes I7 IV7 and V7.
There are various patterns and forms a Blues may take. The most familiar is the 12 Bar Blues.
In a Blues in Bb the three basic chords are:
Notice that in Blues playing I IV and V are dominant sevenths.
The following progression is a basic Blues in Bb. Become thoroughly familiar with it and learn it in all keys. Later we will use various substituted chords to alter and color this basic progression.
The following progression is a variation on the basic Blues pattern.