The Battle of Yu Oc (19 November 1884) was a French victory during the Sino-French War. The battle was fought to relieve the French garrison of Tuyên Quang, under siege by the Tang Jingsong's Yunnan Army and Liu Yongfu's Black Flag Army. The French commander at Yu Oc, Colonel Jacques Duchesne, would later distinguish himself as the conqueror of Madagascar (1895).