Originally the Germans established this as their outpost south of the Rovuma River, and there was a settlement Kionga of 4,000 inhabitants (1910), now Quionga. But in 1916, during World War I, the Portuguese occupied it, and after the war the Treaty of Versailles defined the border as running along the Rovuma, thus allotting the triangle to Mozambique.
On May 29, 1916, 100r postage stamps from Lourenco Marques were overprinted with "KIONGA" and one of the denominations 1/2c, 1c, 2 1/2c, and 5c. These were the only stamps issued for Kionga, and are uncommon, today selling for US$15-$20.