On this day 75 years ago, on September 16, 1950 (August 5, 1950 lunar calendar), the Vietnam-China Border Campaign of the Vietnam Anti-French War began. After the full-scale outbreak of the Anti-French National Salvation War in December 1946, the Vietnamese people have been in the guerrilla warfare stage of defense. On January 18, 1950, the People's Republic of China first recognized and established formal diplomatic relations with the Democratic Republic of Vietnam. China dispatched military and political advisory groups and transported a large number of materials to support the Vietnam War of Resistance. On September 16, 1950, with the support of China, the Vietnam People's Army launched a border campaign in the Vietnam-China border area. First, it launched an attack at Dongxi, annihilating nearly 10,000 enemies, uprooting the French strongholds from Gaoping to Lang Son, liberating 5 cities, and consolidating and expanding the North Vietnam Liberated Area. From then on, the Vietnamese people had a solid rear, and the Vietnamese army took the military initiative in northern Vietnam, gradually moving to the stage of partial counter-offensive.