The koto (箏) is a Japanese plucked half-tube zither instrument, and the national instrument of Japan. It is derived from the Chinese zheng and se, and similar to the Mongolian yatga, the Korean gayageum and ajaeng, the Vietnamese đàn tranh, the Sundanese kacapi and the Kazakhstan jetigen. Koto are roughly 180 centimetres (71 in) in length, and made from Paulownia wood (Paulownia tomentosa, known as kiri). The most common type uses 13 strings strung over movable bridges used for tuning, different pieces possibly requiring different tuning. 17-string koto are also common, and act as bass in ensembles. Koto strings are generally plucked using three fingerpicks (tsume), worn on the first three fingers of the right hand.