The progression shown in Figure 9.9 exemplifies the structure of a minor blues.4The chord structure of the minor blues is characterized by the presence of traditionaltonal progressions. For instance, the tonicization of iv in m. 4 uses a secondary dominant7th, V7/iv, and the motion to V 7 in m. 10 is prepared by the ≤VI7 chord. This particularpreparation of the dominant 7th, ≤VI7–V7, is one of the harmonic trademarks of the minorblues.