Shoumyou is composed with go-in (five notes), sichi-sei (seven tones), and jyuuni-ritsu (12 chromatic semitones) in san-shu (three tunes).
The five notes are a pentatonic scale consisting of five notes called kyuu,syou,kaku, chi, and u, which are equivalent to the Western musical scale of do, re, mi, and so on. The seven tones are the five notes plus ei and hen, each one semitone above and below the pentatonic scale. The three tunes are ryo, ritsu, and chuu Ryo is a succession of the five notes plus two semitones, hen-kyu and hen-chi, ritsu a succession of the five notes only, and chuu a succession of the five notes plus two semitones, ei-shou and ei-u. The 12 chromatic semitones are an octave with 12 tone levels fixed at about half-tone intervals. They are named ichikotsu, tangin, hyoujyou and so on, and, when arranged with some of the five notes, also represent the names of rhythms. Each of the five notes has its own musical characteristics. While Japanese ancient court music known as gagaku has only two tunes, ryo and ritsu, Shoumyou is composed in free combinations of the three tunes as described in the above, with additional coloring of some appropriate extra tones. Thus Shoumyou is rich in expression in an ingenious way and is considered as the source of native Japanese music including heikyoku (also known as Heike-biwa, chanting of "Heike Monogatari" or "The Tale of the Taira Clan" to the accompaniment of a biwa, a type of short flute), jyoururi (narrative ballads chanted to shamisen accompaniment), gidayou (the narrative style of vocal music in Bunraku and Kabuki ), nagauta (long epic songs), and ondo (traditional folk songs).