observers had twice sighted enemy armored fighting vehicles west of An Hoa.

Originally, intelligence estimates had set the start date tor the offensive on 20 July, to coincide with the new moon when illumination would be low. Although speculative, this theory fit a pattern of increased enemy activity during the darkest nights of a given month.' However, when this dare passed without serious incident, intelligence officers revised their estimates to reflect the next new moon phase as the start date: 23 August 196S. In tenuous confirmation ot this supposition, a prisoner revealed that the month of August was to bring the "decisive battle for revolutionary history.""

As III MAF developed intelligence concerning the third offensive, subordinate units prepared for the coming battle. Acting on the reports of enemy tanks and extensive Communist road-building activity southwest of Da Nang, the 1st Marine Division revised its anti-mechanized defense plan to meet the new threat.'' Major General Carl A. Youngdale, who had relieved Major General Robertson as division commander in June, directed his subordinate commanders to review plans for the defense of the Da Nang TAOR and to increase the readiness of their units. Anticipating that the enemy would strike during darkness, he ordered that all units maximize night activities and "reduce day workloads accordingly to allow adequate rest for all hands."'0 In the area surrounding Da Nang, Operations Allen Brook and Mameluke Thrust continued with the participating units frequently shifting their areas of operations in an effort to engage and destroy the major Communist units which would have to concentrate to conduct an offensive of the magnitude III MAF anticipated.

Jusr past noon on 18 August, less than a kilometer west of Marble Mountain Air Facility, a patrol from Company B, 1st Military Police Battalion apprehended a 16-year-old Vietnamese boy who confessed that he was a member of a VC platoon which was hiding nearby. The MPs cordoned off the area and, with the assistance of the South Vietnamese l()6rh Regional Force Company and Company C, 3d Military Police Battalion, conducted a thorough search. Several light contacts with small groups of VC resulted, leading to the discovery of weapons, ammunition, and explosives caches as well as a radio receiver."

Major General Youngdale, in a report to Lieutenant General Robert E. Cushman at III MAF headquarters, noted:

. . . enemy activity has increased .... there are indications that the enemy may be in the latter stages of preparation for his third offensive. As yet, however, there are no indications that the enemy is prepared to conduct a major attack within the next twenty-four hours.'2