Music for Buddhist dances and dance-dramas embraces an immense variety of forms, including the extinct gigaku (introduced from Korea in the early 7th century), certain court dances (bugaku) and nō plays, as well as festivals, processions and other entertainments (shōryō-e, ennen, gyōdō etc.). Many entail the use of masks. Among non-liturgical Buddhist ballads and songs, mōsō-biwa is a recitation by blind monks accompanying themselves on the short lute. Introduced to Japan in the 7th century, it developed above all within Tendai and inspired later biwa narrative ballad genres, notably heikyoku, but many details of its history remain unclear. Other types of Buddhist song include kinds of chant and dance incorporating the nembutsu, the Pure Land formula of invocation to Amida-butsu; go-eika, pilgrims' songs; sōga (or enkyoku), feast songs of the 14th–15th centuries, with metrical texts modelled on kōshiki; sekkyō (or uta-sekkyō), expositions of Buddhist teaching, sung by professional performers in a kabuki-influenced style and even setting, especially in the late 17th and earlier 18th centuries; and saimon (or uta-saimon), a somewhat similar form, at its height during the same period but inspired by Shingon and Shugendō and performed either as street music or as part of puppet plays. The solo repertory (honkyoku) for end-blown flute (shakuhachi), popular from the 17th century, is above all on Buddhist themes and was disseminated by mendicant friars of the Fuke-shū, a Zen-inspired sect (see §II, 5 above). Lastly, modern Japanese composers who have written on Buddhist themes include Mayuzumi Toshirō (1929–97) and Fukushima Kazuo (b 1930).