As mentioned previously, the 12 Bar Blues form can be applied to any key. The easiest way to do this is to memorize the chord pattern in Roman numerals as shown here. Although there are many variations, the simplest form of the 12 Bar Blues uses only chords I , IV and V .
Here is a 12 Bar Blues in the key of G. The chords are played with the right hand, while the left hand plays a common Blues and Boogie accompaniment pattern.