20 Dec 1969: Anniversary of the Capture of North Vietnamese Notebooks
On December 20, 1969, soldiers of the U.S. Army's 1st Division were on patrol in Binh Duong Province of the Republic of Vietnam (South Vietnam) and spotted an antenna wire protruding from the ground. What they actually discovered was one of a well-developed network of tunnels of the Democratic Republic of Vietnam (North Vietnam). Inside was a cache of over 2,000 intercepted U.S. and South Vietnamese voice transmissions. They also captured 13 of the 18-person communications unit with receivers and other equipment of Chinese, Vietnamese, and U.S. origin. These notebooks provided the North Vietnamese and Viet Cong with information on the location of allied units, disposition of forces, and other importance intelligence.