Watch the Minor Blues 9 online guitar lesson by Brad Carlton from Bluesology 2

In this lesson, progression 6, the I Dom 7th altered will be inserted in bar four to create tension and movement to the iv minor chord (V7 to i in D minor). In bar nine the ii minor 7 flat 5 preceding the V7 altered is introduced.
In lesson 4 we used the flat VI major 7th. Here in progression 7, the flat VI Lydian Dominant will be used in measure 9. Check out the flat V substitution in measure 12.