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
Bouzouki the pair are tuned to the same note. In the two lower-pitched (bass) courses, the pair consists of a thick wound string and a thin string tuned an octave apart. On the bouzouki the lower-pitched string comes first in these courses, the reverse of most other instruments with octave-paired courses (such as the 12-string guitar, charango or bajo sexto). These 'octave strings' add to the fullness of the sound and are used in chords and bass drones (continuous low notes that are played throughout the music). The guitar-like tuning was introduced by composer and soloist Manolis Hiotis, who found it