The most widely accepted theory of the etymological origin of the word itself traces its appearance to the text in 'Biography of Lucun' in the series of "Jiu Tang Shu" (Old Tang History), which describes that Lucun, a Tang musician who lived in the early seventh century, created a vertical flute tuned to a 12 tone scale, with the Oshikicho tone being the Tang standard tone (according to the 12-tone Japanese scale, the equivalent of the tone D on the scale of the West); the dimension at which this tonic was obtained is said to have been one shaku and eight sun, thus the name 'shakuhachi.'
語源に関する有力な説は、『旧唐書』列伝の「呂才伝」の記事によるもので、7世紀はじめの唐の楽人である呂才が、筒音を十二律にあわせた立笛を作った際、中国の標準音の黄鐘（日本の十二律では壱越西洋音階のD）の音を出すものが一尺八寸であったためと伝えられている。