Irish bouzouki Dónal Lunny, who replaced the octave strings on the two lower G and D courses with unison strings, thus reinforcing their lower frequencies. Soon after, on a visit with Irvine to the workshop of luthier Peter Abnett, Lunny commissioned a bouzouki to the specifications of a classic, 4-course Greek bouzouki but with unison strings and a three-piece, partially staved back. Since then, the instrument has been adapted for Irish traditional and other styles of folk music. The original Greek bouzouki was a three course/six-string instrument ("trichordo"). In the 1950s, a four course/eight-string ("tetrachordo") version was developed. The newer "tetrachordo" bouzouki
Irish bouzouki (or slightly radiused) tops and backs. The Irish bouzouki has also become integrated into some other western European musical traditions over the past forty years. Popularly used in the music of Asturias, Galicia, Brittany, Spain, and even the Scandinavian countries (in fact, there is even now a new Nordic branch of the instrument, having been modified further to suit the unique requirements of those musics). The instrument's role is usually a combination of interwoven accompaniment (usually a mix of open-string drones, two note intervals, bass lines and countermelody) and melodic play. Instrumental arrangements by musicians such as Ale Möller from