January 9, 1973: a barter trade zone was established in Mindanao

On January 9, 1973, a barter trade zone was established in Mindanao by virtue of Presidential Decree No. 93. Under the decree, the government allowed businessmen from the Sulu Archipelago, Balabac Islands, and Zamboanga del Sur to trade with neighboring islands and sell imported items within the region without tariff duties.