Botswana and Namibia have accepted that their mutual frontier was determined by Anglo-German Treaty of1890. The Treaty defined a frontier of the sphere of influence of the UK and Germany saying that it follows, inter alia, the center of the main channel of the Chobe River around the Kasikili/Sedudu Island. The River bifurcates in two channels around the Island and after the Island the channels merge again in the same River. The Treaty did not determine which of the two channels was the main channel and it became cause of a dispute. The parties agreed that the International Court of Justice resolves the dispute about the frontier and the status of the Kasikili/Sedudu Island applying the 1890 Treaty and general rules and principles of international law. The Court decided that the main channel is the north channel, that the Island is a territory of Botswana and that the navigation on the both channels remains free and under equal national treatment for vessels of the both sides. The Court based its conclusion about main channel on the common meaning of the term as it defined in relevant literature. The support for the conclusion was found in a report of local authorities of the both sides and a report of a common expert group, established by the two parties. Namibia did not succeed to convince the Court that Namibia had acquired the Island by prescription on the basis of long presence of Namibian tribe Masubia on the island, since the Court did not accepted that the tribe pursued sovereign power.