Three-chord song

A three-chord song is a song whose music is built around three chords that are played in a certain sequence. A common type of three-chord song is the simple twelve-bar blues used in blues and rock and roll. Typically, the three chords used are the chords on the tonic, subdominant, and dominant (scale degrees I, IV and V): in the key of C, these would be the C, F and G chords. Sometimes the V7 chord is used instead of V, for greater tension.