The 12 Bar Blues in Db contains the chords Db7 (I chord), Gb7 (IV chord) and Ab7 (V) chord. Below is the 12 Bar Blues starting on Db7.
12 Bar Blues in Db (Jazz Variation)
The Jazz variation of the 12 Bar Blues in Db adds some extra chords. The 12 Bar Blues structure remains the same, but certain chords are substituted. For example, the Db7 chord in the fourth bar is substituted with an Abm7 moving to an Db7 chord.