Originally, two pieces of divided shaku or two shaku were provisionally used in singing, and it is thought that later they were conventionalized and established as new instruments.
そもそもは歌う際に臨時に笏を割ったもの、または2つの笏を用いて、それが後に様式化し、独立した1つの楽器として成立したと考えられる。