MAPUTO, Sept. 11 -- WHEN the gates of the 61st Maputo International Trade Fair (FACIM) closed recently, Tanzania left behind more than an exhibition pavilion.

It left with a question that may be more important than the exhibition itself: How can Tanzania turn the relationships, market intelligence and investment opportunities identified in Mozambique into sustained economic engagement between the two countries?

The question matters because FACIM demonstrated something important. Mozambique is not simply a market for Tanzanian products. It can also be a destination for Tanzanian investment, technology, partnerships and regional expansion.

This is where the next chapter of Tanzanias economic diplomacy should begin. FACIM as a starting po...