DAR ES SALAAM, Nov. 2 -- FEW countries in Africa share a bond as deep and enduring as that between Tanzania and Mozambique. Our peoples fought side by side for freedom.

Our leaders built a friendship that has withstood the test of time for more than half a century.

We share the Ruvuma River, the Indian Ocean coastline and the rich Swahili heritage that stretches along it. Yet, an important question must be asked: Has this extraordinary political relationship been matched by an equally strong economic partnership?

The honest answer is: Not. Trade between our two countries remains modest compared with the strength of our historical ties, while numerous economic opportunities on both sides of the border remain untapped.

This is where eco...