Conflict Magazine #6.
From the game's introduction:
Hue was the site of the January, 1968 battle between the North Vietnamese Army (NVA) and its guerrilla allies, the Viet Cong (VC), against the 1st Division of the Army of the Republic of South Viet Nam (ARVN) and, the best combat troops in the area, elements of the United States Marine Corps (USMC). Vietnamese General Giap directed his communist troops in a concerted attack during Tet (the lunar New Year), successfully overrunning [sic] Hue and starting a bloody battle to retake the city.
"The battle for Hue was unique, in that it was a medieval city being attacked with modern weapons. The moats and walls presented new sets of tactical problems. The battle was a combination of World War II street fighting and medieval siege warfare, with almost all participants carrying [sic] a fully automatic weapon. If the rules seem peculiar at times, remember that it was a very peculiar battle."