1967: The Era of Big Battles in Vietnam – The New York Times

“By never allowing their large units to engage American large units, the Viet Cong and North Vietnamese units could remain organizationally intact and live to fight another day. The “era of big battles” was supposed to put the Americans on an offensive footing, but 70 percent of all contacts were initiated by the Viet Cong and North Vietnamese. The Communists were fighting the war on their own terms and chose when, where and how long to fight, which ultimately would result in victory.”