International Court of Justice — Merits — Boundary dispute — Dispute between Botswana and Namibia submitted to Court by Special Agreement for final and binding determination — Determination of boundary around Kasikili/Sedudu Island — Determination of legal status of Kasikili/Sedudu Island — Applicable law — Anglo-German Treaty, 1890 — Rules and principles of international law — United Nations Charter — Charter and resolution of Organization of African Unity — Principle of uti possidetis — Respect for frontiers existing upon national independence — Anglo-German Treaty, 1890, Article III — Delimitation of spheres of influence in south-west Africa — Boundary line following centre or thalweg of main channel of Chobe River — Whether northern and western channel constituting main channel as asserted by Botswana — Whether southern channel constituting main channel as asserted by Namibia — Boundary between Botswana and Namibia around Island — Whether Island part of territory of Botswana or Namibia — Whether Namibia having prescriptive title to Island

Rivers — Riverain boundary — Chobe River — Main channel of Chobe River — Boundary between Botswana and Namibia around Kasikili/Sedudu Island following main channel of Chobe River — Anglo-German Treaty, 1890, Article III — Location of main channel being main dispute between Parties — Whether northern and western channel constituting main channel as asserted by Botswana — Whether southern channel constituting main channel as asserted by Namibia — Boundary between Botswana and Namibia around Island

Rivers — Chobe River — Kasane communiqué — Undertaking between Parties — Nationals of and vessels flying flags of Botswana and Namibia to enjoy equal national treatment in two channels of Chobe River around Island — Navigation and environmental protection

Treaties — Interpretation — Application — Anglo-German Treaty, 1890 — Vienna Convention on the Law of Treaties, 1969, Article 31 — Article 31 reflecting customary international law — Anglo-German Treaty, 1890, Article III — Delimitation of spheres of influence in south-west Africa — Boundary line following centre or thalweg of main channel of Chobe River — Whether centre and thalweg synonyms — Determination of location of main channel — Real dispute between Parties — Whether northern and western channel constituting main channel as asserted by Botswana — Whether southern channel constituting main channel as asserted by Namibia — Ordinary meaning of words “main channel” — Criteria for determination — Relevance and applicability — Depth — Flow — Bed profile configuration — Navigability — Object and purpose of 1890 Treaty — Travaux préparatoires to 1890 Treaty — Subsequent practice of parties to 1890 Treaty — Map evidence

Territory — Sovereignty — Kasikili/Sedudu Island — Determination of legal status of Island — Whether Namibia and predecessors having prescriptive title to Island — Whether Special Agreement precluding examination of prescriptive claim — Whether acts of State authority by Namibia on Island

State succession — European colonial powers partitioning Africa — Great Britain and Germany signing treaty delimiting respective spheres of influence in south-west Africa — Botswana gaining independence in 1966 — Namibia gaining independence in 1990 — Delimitation of boundary between Namibia and Botswana around Kasikili/Sedudu Island — Determination of legal status of Island — Anglo-German Treaty, 1890 — Rules and principles of international law — United Nations Charter — Charter and resolution of Organization of African Unity — Principle of uti possidetis — Respect for frontiers existing upon national independence