The tube zither is a stringed musical instrument in which a tube functions both as an instrument's neck and its soundbox. As the neck, it holds strings taut and allows them to vibrate. As a soundbox or it modifies the sound and transfers it to the open air. The instruments are among the oldest of chordophones, being "a very early stage" in the development of chordophones, and predate some of the oldest chordophones, such as the Chinese Se, zithers built on a tube split in half. Most tube zithers are made of bamboo, played today in Madagascar, India, Southeast Asia and Taiwan. Tube zithers made from other materials have been found in Europe and the United States, made from materials such as cornstalks and cactus. There are both round and half tube zithers, as well as tube zithers with the strings cut out of the bamboo body, idiochordic, or, rarely, have separate strings, heterochordic. Cultural connections The areas where the bamboo tube zither has been used was connected by trade and migrations of people. One widespread group who still have some members using the bamboo-tube zither today were the Austronesian peoples, inhabiting an area that includes Madagascar, Southeast Asia, Oceania and Taiwan. Musicologists use iconography, linguistics, and literature to look for clues about existence and traits of musical instruments in the past, as well as modern instrument and variations among them. From these clues they create a history, basing their story of the instrument on the clues they have uncovered. Existing instruments, names in different languages, methods of manufacture and playing, music theory and tonal systems all offer clues to instrument origins. Among the historical trends in the background of the bamboo tube zither, traders from India sailed east and "passed the Malay peninsula" by the 6th century b.c. Indonesians sailed west to Madagascar by the 1st century A.D. By the 3rd century a.d, Buddhists were making statues in Java, and by the 7th century A.D. the "Indianized" Srivijaya empire (650-1377) was founded in Sumatra. The Khmer empire (802-1431 a.d.) was founded in the 9th century a.d. Wars among countries (including the Khmer Empire, Champa) (192–1832) and Đại Việt caused people to migrate overland, including a defeated tribe from the Tonkin plains in modern Vietnam moving overland eastward to Assam near North India. Currently known evidence in pictures for the tube zither and bar zither dates to between the 7th