Sanjugen (30-strings Koto) is a kind of So or Koto (a long Japanese zither with 30 strings).
It is created in 1955 by Shuretsu MIYASHITA the first, a So player and composer, and improved by Shin MIYASHITA, his son.
It is a large type of So with 30 strings and its size is around 235cm in length and around 55cm in maximum width, and it belongs to an incomplete zither with mobile frets. It is made to increase the low and high ranges of traditional Jusangen So (13-string Koto). The instrument is designed to extend the interval from the ryukaku (the fixed bridge on the performer's right) to pins and to have the function of percussion instruments so that a player can play strings (atonal) or beat (hit) there. Material of the instrument is the same as the traditional So and each string is twisted around a pin at the head portion just as Jushichigen So (17-string Koto). The extra-thick strings (thicker than the strings for Jushichigen So) are used for tenor note strings and made strong enough for beating at full strength with a hand as percussive. The thickness of the strings are changed in about threes of strings and 17 strings in the tenor note part are made of silk and 13 strings in the treble note part are made of tetrone. Bridges of Koto are generally large and the largest one (for the tenor notes) is around 8.5cm-high and the smallest one is the same as those of Jushichigen So. Bridges of a Koto are designed not to line up diagonally in a single line by adjusting the thickness of strings and the height of bridges.
It is used in modern music and is played with a pick and three fingers of the right hand (thumb, index and middle finger).
Solo for 30-string Koto' composed by Shuretsu MIYASHITA the first (won Arts Festival [the Agency for Cultural Affairs] Excellence Award played by Shin MIYASHITA)
Symphonia for S.M.' composed by Makoto MOROI (won the Arts Festival Grand Prize played by Shin MIYASHITA)
Nimen no Sanjugen to dagakki no tameno Hibiki' (sounds for two 30-string Kotos and percussions) composed by Shin MIYASHITA (1972, commissioned by NHK)
Sanjugen to dagakki no tameno Hibiki' (sounds for 30-string Koto and percussions) composed by Shin MIYASHITA (1972, commissioned by NHK)
Sanjugen, So, Shakuhachi, dagakki no tameno "Kairyu ni notte"' (Going with Kairyu, the ocean current for 30-string Koto, 13-string Koto, Shakuhachi, and percussion) composed by Shin MIYASHITA (1993, commissioned by Nihon Sankyoku Kyokai)
Sanjugen, Shakuhach, Uta ninaru "Minamijima"' (Minamijima becoming 30-string Koto, Shakuhachi, and songs) composed by Shin MIYASHITA (1995, commissioned by the Agency for Cultural Affairs)