Moving away from the population centre of Java, Bali and Madura, we explore the folk music of Sumatra, the Riau Islands, and the Mentawi Islands in the northwest of the country. We start with the people living in the interior uplands of Sumatra, the Toba and the Minangkabau, the latter of which being the largest matrilineal society in the world. The Toba are famed for their intricate Gondang percussion music, whereas the Minangkabau have a form of chamber music that features one or two singers with a single instrument.