The upe (or upi) is a traditional headdress worn by men in parts of Bougainville (an autonomous region of Papua New Guinea) to symbolise their transition to adulthood. The term is also used to refer to the process of undergoing the transition and to the initiates themselves. The upe is the central figure of the flag of Bougainville and forms the crest of the emblem of Bougainville. It is made of tightly wound straw.