The koto (Japanese: 箏) is a traditional Japanese stringed musical instrument, similar to the Chinese zheng, the Mongolian yatga, the Korean gayageum and the Vietnamese đàn tranh. The koto is the national instrument of Japan. Koto are about 180 centimetres (71 in) length, and made from kiri wood (Paulownia tomentosa). They have 13 strings that are strung over 13 movable bridges along the width of the instrument. Players can adjust the string pitches by moving the white bridges in the picture before playing, and use three finger picks (on thumb, index finger, and middle finger) to pluck the strings, otherwise known as plectra.