Buka is an island separated by a narrow strait from the larger island of Bougainville to the south. The people of Buka and northern Bougainville speak related Austronesian languages, and are sometimes considered a cultural unit. The primary source on this culture, Beatrice Blackwood's 'Both Sides of Buka Passage', is based largely on fieldwork carried out in the Tinputz-speaking village of Kurtatchi on the north coast of Bougainville.