DADGAD or D modal tuning was popularised by British folk Guitarist Davey Graham. Graham employed the tuning to great effect in his treatments of celtic music, but also the folk music of the East including India and Morocco. The suitability of DADGAD to Celtic music is that it facilitates the use of a number of moveable chords which retain open strings which act as a drone on either the bass or treble strings, approximating the voicings used in traditional celtic pipe music. Other exponents of the tuning include Pierre Bensusan, Bert Jansch and Richard Thompson.