12 bar Blues is a pattern of chords which repeats every 12 bars. It is the most common progression in Blues music, and is used extensively in Rock and Jazz as well. The following example is a 12 bar Blues using all the inversions of the chords Cm, Fm and Gm.
This example contains much use of implied slash chords. The left hand part consists of alternating octave notes. Practice each hand separately at first if necessary.