A remarkable number of the traditional forms of Japanese music, dance, and theater have survived in the contemporary world, enjoying some popularity through reidentification with Japanese cultural values. Traditional music and dance, which trace their origins to ancient religious use - Buddhist, Shintō, and folk - have been preserved in the dramatic performances of Noh, Kabuki, and bunraku theater. Ancient court music and dance forms deriving from continental sources were preserved through Imperial household musicians and temple and shrine troupes. Some of the oldest musical instruments in the world have been in continuous use in Japan from the Jōmon period, as shown by finds of stone and clay flutes and zithers having between two and four strings, to which Yayoi period metal bells and gongs were added to create early musical ensembles. By the early historical period (sixth to seventh centuries CE), there were a variety of large and small drums, gongs, chimes, flutes, and stringed instruments, such as the imported mandolin-like biwa and the flat six-stringed zither, which evolved into the thirteen-stringed koto. These instruments formed the orchestras for the seventh-century continentally derived ceremonial court music (gagaku), which, together with the accompanying bugaku (a type of court dance), are the most ancient of such forms still performed at the Imperial court, ancient temples, and shrines. Buddhism introduced the rhythmic chants, still used, that underpin Shigin, and that were joined with native ideas to underlay the development of vocal music, such as in Noh.