The jūshichi-gen was invented in 1921 by Michio Miyagi, a musician who felt that the standard koto lacked the range he sought in a traditional instrument.
[citation needed] In 2000, the musician Naito Masako, a member of the Seiha faction of the Ikuta school, constructed a new version of the 17-string koto called poppukon (popcorn), finished in bright colours such as pink, yellow, or blue.
The strings used are typically silk threads that are yellow in colour and give the instrument a deep sound.
Musicians who play the bass koto have also invented new techniques for playing the instrument, utilising more of the left hand to produce a sound that more adequately displays the instrument's deeper sound, and allows for more pitches to be created on one string.
The strings are also plucked over the cylindrical holder to create a sudden "shrill" sound.