koto, a Japanese string instrument related in structure to the zither. It consists of an elongated rectangular wooden body, strung lengthwise with 7 to 13 silk strings. The uniformly long strings are tuned to one of several standard tunings by moveable wooden bridges. The koto is placed horizontally on the floor with the player seated behind it, and it is plucked with the fingernails or with a plectrum. The instrument was introduced to Japan in the 8th cent., and its present repertory has developed since the 16th cent. It is played solo and in duets, is used to accompany a singer to play in specific small ensembles.

Japanese musical instrument, a long zither with movable bridges and usually 13 strings. It is placed on the ground or a low table, and the strings are plucked by plectra on the fingers of the right hand while the left hand alters the pitch or ornaments the sound of individual strings by pressing or manipulating them on the other side of each bridge. The koto is played solo, in chamber ensembles—especially with the shakuhachi (a bamboo flute) and the samisen (a fretless lute)—and in gagaku music. The koto is Japan's national instrument.

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