FOOD OF THOUGHT:
If this Malawi / Tanzania dispute over lake nyasa were to be based on colonial era contracts, then 10 kilometres from the coast to interior in Tanzania mainland/Tanganyika belongs to Zanzibar and Mombasa belongs to Zanzibar. According to 1886 Agreement between the Sultan of Zanzibar and The then German Colonialists.
History taught us many things but sometimes it can become controversial especially over territorial disputes take Pearl Harbor-Hawaii (USA/JAPAN/RUSSIA(claims portion)), Daegwu islands-CHINA, JAPAN, SOUTH KOREA, Falkland/Malvina islands-UNITED KINGDOM/ARGENTINA. I think they should be claimed as no man's land, no man's lake or no man's islands for that matter if it involves egos, selfishness and superiority.