bowed chordophones. Bamboo The bamboo-tube zither exists in the 21st century in pockets from Madagascar, to India, Southeast Asia and the Philippine Islands of Northern Luzon and Mindanao. Historically, it was found in India and China, where in the 21st century the Rudra veena and non-bamboo guzheng are modern relations. The basic instruments were constructed by cutting strips into the outer edges, raising the strips with wedges to create tension and make idiochord strings. They could be tuned by the positioning of the wedges, tightening and loosening the bamboo-strip strings. Beneath the strips, the holes started below the strips of bamboo were expanded downward, until they went all the way through the side of the tube. Modern instrument makers in Madagascar, Cambodia, Thailand, and Vietnam have taken advantage of modern materials. Fishing line, wire and other modern string materials have been repurposed as musical instrument strings, with pegs to tune the instruments. There is less fall-off of the note with the new materials and the sound of the instruments are different. The instruments are connected with gongs in cultures in Burma, Cambodia, Vietnam, Indonesia and the Philippines. When hammered, the zithers with bamboo strings have a gong or bell-like tone which rings and falls off. In Indonesia, there have been gong-ensembles made entirely of bamboo instruments, and some groups use a word for gong in the instruments' names (such as [gong bamboo]).<--verify--> Where gongs are a public instrument, the polychord bamboo-zithers can be used privately in the home. Furthermore, with a tube-zither, a musician can play music that normally takes an entire group of gongs. Kolitong and kulibaw mimic the cyclic sequence of the gangsa (ensembles of flat gongs). For this, the six strings of the kolitong are tuned exactly to the pitch of the gongs. Cambodia: Kong Indonesia: Kolintang gong) Kolitong zither Tagalog: Agong Sumatra: Ogoeng Vietnam: Goong Africa The tube zither, called valiha, arrived in Madagascar in the 15th century a.d. with the Hova people, a Malay people. Two forms exist. The traditional form has as many as 14 strings cut and raised from the bamboo tube. Starting in the 20th century, the bamboo strips were replaced by metal strings, changing the instrument's sound. Africa also uses the raft zither, in which tube zithers are put together into a single musical instrument. One example of a raft zither is the Totombito zither, from Congo. Other African examples may