Strings (tennis) be more durable than many other types of strings due to its outstanding tension retention. This may help to offset the high initial cost. The use of a dense string pattern also generally improves the longevity of natural gut. Natural gut is produced by drying fibers extracted from a part of the cow intestine called the serous membrane, or serosa, which contains collagen designed to withstand the stretching and contraction of the intestine. It is this elasticity that makes the fibers useful for tennis string. Sheep intestines have also been used for racquet strings in the past. The first natural
Koto (instrument) Koto (instrument) The is a Japanese stringed musical instrument derived from the Chinese zheng, and similar to the Mongolian yatga, the Korean gayageum, and the Vietnamese đàn tranh. The koto is the national instrument of Japan. Koto are about length, and made from "kiri" wood ("Paulownia tomentosa"). They have 13 strings that are usually strung over 13 movable bridges along the width of the instrument. There is also a 17-string variant. Players can adjust the string pitches by moving the white bridges before playing. To play the instrument, the strings are plucked using three finger picks (thumb, index finger, and