The Ichigenkin 一 絃 琴 literally "one-string zither", is a Japanese one-string zither.
The raw silk string is plucked with a tubular pick on the index finger of the right hand, while a tubular ivory element that resembles a guitar sled over the middle finger of the left hand to vary the pitch.
The instrument was very popular with samurai, writers and priests. Today there are very few players. There is only one unbroken Ichigenkin transmission line.
Seikyodo Ichigenkin, whose current hereditary grand master is Issui Minegishi.
In 1820 a two-string version was developed. The Yakumogoto (nigenkin), associated with the Shinto religion
Maybe it was one insapiration for Lew Sergejewitsch Termen to develop the Theremin Instrument 1920. There are similarities in playing style and hand position