After the VC attack and the successful counter-offensive by the Army of the Vietnam Republic (ARVN) on Highways 19 and 1 during the 1964 communists' winter-spring campaign, enemy activity in the northern portion of II Corps dropped to a new low. The VC used this period to both regroup and reconstitute depleted units, at the same time continuing to infiltrate additional regular army regiments from North Vietnam. Intelligence reports during the spring indicated that large-scale infiltration was continuing, the enemy moving battalions initially into Kontum Province and then continuing the move to the south and southeast into Pleiku and Phu Bon Provinces. It soon became evident from intelligence sources that the VC were increasing their build-up for an offensive which it was estimated would begin during the bad weather of the summer monsoon.
This communist build-up was highlighted by General Wheeler, Chairman of the Joint Chiefs of Staff, at an address in early May: "Hanoi sustains the insurgency through a never-ending stream of personnel, arms, ammunition, and other supplies infiltrated into South Vietnam. Hanoi has now gone so far as to infiltrate at least one entire North Vietnamese Army battalion and, frankly, there are probably more." The NVA battalion he mentioned was from the 101st Regiment of the 325th Division which had been identified by documents and prisoners during a search-and-destroy operation conducted by ARVN troops west of Kontum City. It was the first battalion-sized NVA unit to be identified in South Vietnam.
To determine the strategy to be used in meeting this anticipated VC offensive, a meeting was held at II Corps headquarters in Pleiku by representatives of General William C. Westmoreland's staff headed by Brigadier General William E. DePuy, then MACV J-3, and the ARVN Joint General Staff (JGS) headed by General Nguyen Huu Co, former II Corps commander who had been appointed head of the ARVN military forces. It was agreed that due to the increased build-up of enemy troops, II Corps during the rainy season would adopt essentially a defensive posture in the highlands. The new II Corps commander, Major General Vinh Loc, in line with the defensive posture to be taken by his corps, analyzed the "military worth" of all key outposts and districts towns. He decided that those posts in exposed positions would be held as long as possible in order to cause highest casualties to the attacking communist forces. If after an attack it was determined that it would be to our military disadvantage to reinforce at that time, due to lack of troops or air support, the posts would be ordered to withdraw, using escape and evasion tactics if necessary. Those earmarked as keys to the defense of vital areas within each province were to be held at all costs. Contingency plans were drawn up and ARVN general reserve troops and U.S. and ARVN Air Force airlift and fighter planes were earmarked as the nucleus of a "fire brigade" which could be rushed to critical areas in the highlands. It was hoped that our superior mobility would allow the rapid concentration of troops by air from all over the corps area so as to meet the VC threat and then to return these troops to their normal defensive assignments before the VC were able to react. With these contingency plans prepared, the highland garrisons strengthened their defenses, launched limited attacks designed to locate the VC and harass their build-up, and awaited the rains.
Colonel Theodore Mataxis
Excerpt from VC Summer Monsoon Offensive [May 1966]
(Vietnam Center Archive)