12-bar blues
Twelve bars built from three dominant 7th chords. It is the foundation of blues, early rock and roll and countless jams.
12-bar blues in every key
The numerals stay the same in every key; only the chord names change. The easiest keys on guitar are A major, D major, E major.
Questions
What chords are in the 12-bar blues progression?
In A major it is A7, A7, A7, A7, D7, D7, A7, A7, E7, D7, A7 and E7. In any other key, use the same numbered steps (I7 – IV7 – I7 – V7 – IV7 – I7) of that key's scale.
What is the easiest key for 12-bar blues on guitar?
A major, D major and E major use open chords, so they are the easiest places to start.