evidence: What about the Kafia Kingi enclave? I defer to Edward Thomas, who wrote an entire book (PDF, 2010) on this remote and sparsely inhabited region of Africa, long used as slave hunting grounds by Arab slave traders. Kafia Kingi was part of southern Sudan at independence in 1956, but in 1960 jurisdiction over the area was transferred to northern Sudan. [...] On the other hand, it is not clear whether South Sudan is actively pursuing a claim on Kafia Kingi. The fledgling state has a lot on its plate, and cannot afford to confront Sudan militarily. Official maps of South Sudan are hard to come by: The only map available on the government’s official website omits both Abyei and Kafia Kingi, though likely for the same reason it is missing from the dataset used by Wikipedia and OSM. For the International Court of Justice or other arbitration courts, however, such omissions will over time come to undermine territorial claims. Edward Thomas, meanwhile, in his book suggests that Khartoum is holding on to Kafia Kingi as a bargaining chip, because its sparse population and mineral wealth makes it easily tradable for concessions elsewhere along the border.