- Sō, Gakuso or Koto
A thinner and shorter transverse bamboo flute with six finger holes, producing higher notes, D♯(closed), F♯, G, A, B, C♯ and E’.
A mouth organ consisting of a wooden reservoir which is covered with a plate of water buffalo horn. Seventeen thin bamboo pipes are inserted through this cover. At the lower end of each pipe a metal reed, like a harmonica reed is fixed except in two pipes which are mute. The instrument is played by blowing through the mouthpiece fixed to the reservoir. The sound of the reed is so tiny and high that it can scarcely be heard. Therefore, on the upper inside of each pipe, a thin, short slit is made which is approximately about 2 cm in length. The air column in the part of the pipe between the closed bottom of the pipe and lower end of the slit, resonates with the vibration of the reed, and makes the sound louder and low enough to be audible.
Since the instrument produces a harmony of five or six notes, the performer has to sound the correct pipes. Close to the cover, each pipe has a tiny finger hole. When the finger hole is open resonance does not occur, but when closed there is resonance and the pipe sounds.
A thirteen-stringed long zither, 189cm in length, with silk strings, tuned by thirteen wooden bridges in six ways, according to the tonality used. The strings are plucked with three picks, which are made of bamboo and fixed to the thumb, the index finger, and the middle finger of the right hand by leather bands.