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
Guqin strings silk strings for their refinement of tone. Further, it is the case that nylon-wrapped metal strings can cause damage to the wood of old qins. Many traditionalists feel that the sound of the fingers of the left hand sliding on the strings to be a distinctive feature of qin music. The modern nylon-wrapped metal strings were very smooth in the past, but are now slightly modified in order to capture these sliding sounds. Although silk strings tend to break more often than metal nylon ones, they are stronger than one may be led to think. Silk is very flexible, and