With both fixed-wing and helicopter gunships and more than 120 artillery pieces ranging from 4.2-inch mortars to 175 mm guns, Robertson was confident that he could counter any threat that the enemy posed to Da Nang despite the thinness of his manned defenses.

According to intelligence reports, on 15 January, Group 44, the forward headquarters of the PAVN/VC Military Region 5, moved from the hills in western Quảng Nam Province, to an advance position on Gò Nổi Island.

From the details of the other recovered documents, the VC obviously were making an extensive reconnaissance of the Da Nang area giving descriptions of military structures, distances, weapons and other information that would be of value to an attacking force.

On 29 January, a local village chief told the security officer of the Naval Support Activity at Camp Tiensha that about 300 VC would attack the Marble Mountain transmitter that night.

Another PAVN soldier, who infiltrated from North Vietnam after receiving a year's training as a radioman in Hanoi, was thrust into one of the attacking battalions south of Da Nang so hastily that he never learned the name of his unit let alone those of his officers.

For example, while the R-20th attempted to maintain a full complement of 400 men through the recruitment or impressment of local villagers and infiltration of North Vietnamese "volunteers," intelligence sources rated the unit only "marginally effective.

The attack force would consist of two groups, one to move by land and the other by water to knock out the bridge separating the city from Tiensha Peninsula and to capture the I Corps headquarters.

At 16:00, one of the Stingray units, using the codename Saddle Bag, situated in the mountains just south of a bend in the Thu Bồn River below An Hòa Combat Base, about 20 miles (32 km) southwest of the Da Nang, reported observing about 75 enemy soldiers wearing helmets and some carrying mortars.

[1]: 144 Shortly after midnight, Marine sentries from the 1st MP Battalion, posted near the main I Corps Bridge connecting Da Nang to the Tiensha (Tiên Sa) Peninsula, spotted two swimmers near the span.

[1]: 144–5 In scattered and intermittent attacks beginning before 02:00 and lasting about one-half hour, PAVN/VC gunners fired both mortars and rockets that landed near positions of Marine artillery, antiair missiles, and the Force Logistic Command at Red Beach Base Area.

[1]: 147 Major General Raymond Murray, the III MAF deputy commander, remembered that he heard a "hell of a lot of racket" and "woke up… [to] the airfield at Da Nang… being rocketed."

Employing small arms fire, satchel charges, Rocket-propelled grenades (RPGs) and Bangalore torpedoes, the sappers thrust through blown gaps in the Marine wire.

With covering fire provided by 81mm and 82 mm mortars, about a reinforced company reached the I Corps headquarters compound actually located within the city of Da Nang just outside the northern perimeter of the Air Base.

Shortly after 04:45, General Lãm ordered the ARVN 4th Cavalry Regiment, a Ranger battalion and a detachment of National Police to augment the units in Hòa Vang and the headquarters personnel forces in the compound.

Hill received a telephone call at 03:45 on the 30th from Colonel Thomas Randall, the III MAF G-3, who asked him "to send three platoons to blocking positions south of I Corps headquarters."

According to Washington Post correspondent Don Oberdorfer, Lãm pointed with his swagger stick to the enemy's firing positions on the large map in the room and said: "Milantoni, bomb here.

On the ground a patrol from Company A, 1/7 Marines, operating below the battalion's command post on Hill 10, saw about 10 PAVN soldiers just south of the Túy Loan River preparing positions.

To the south of the Air Base, other PAVN/VC main force units attacked the District Town of Điện Bàn and the provincial capital of Quảng Nam, Hội An, on Route 4.

[1]: 153 South of the Hải Vân Pass, in the northern portion of the Da Nang TAOR, in the 2/7 Marines sector, the PAVN were able to close Highway 1 temporarily, but failed to penetrate Allied defenses.

According to Marine intelligence sources, Rummage may well "have rendered a reinforced battalion combat ineffective, forcing the enemy to modify his plans at a critical time."

ARVN intelligence officers speculated that the battalion from the PAVN 4th Regiment was supposed to have spearheaded the attack on the city of Da Nang the previous day, but arrived too late to influence the battle.

In the 3/7 Marines area of operations, about 2,000 meters west of Hill 55 on the other side of a bend in the Yen River, a squad from Company L at 11:45 ran into what eventually turned out to be a fairly large-sized PAVN unit.

The III MAF Command Center later that evening radioed MACV in Saigon: "Although the enemy has suffered heavy losses within his local and main force VC units during the past two days, he still possesses a formidable threat utilizing [PAVN] troops poised on the periphery of the Da Nang TAOR.

PAVN/VC gunners, however, continued to be active and shot down a Marine CH-46 attempting to insert a reconnaissance team into a landing zone in the hill mass in the western sector of Da Nang below the Túy Loan River.

Because of the location of Hill 65, just above Route 4 about 4,000 meters west of the district town of Đại Lộc and below Charlie Ridge (15°56′10″N 108°05′42″E / 15.936°N 108.095°E / 15.936; 108.095), where the VC had heavy machine gun emplacements which precluded any helicopter lift, the Marine company had to make the move on foot.

Further to the east Company G, 2/3 Marines, at the battalion's command post about 500 meters north of Điện Bàn town, remained as the division mobile reserve mounted in LVTP-5s and supported by tanks.

Marine commanders and staff officers could only speculate that the enemy was probably infiltrating north in small groups to "predetermined rallying points" for a further assault either on the city or on the Air Base.

On 2 February, the Marines received a report that the PAVN 2nd Division had moved its headquarters 4 miles (6.4 km) north, to a position above Route 4, from its previous location on Go Noi Island.

It was decided that two battalions from the Americal Division code-named ‘’Task Force Miracle’’ would be moved into the northern sector of the 3/5 Marines near Route 1 south of the Cầu Đỏ.

Only the 7th Marines to the west experienced an increase in incidents as PAVN/VC troops moved through the western TAOR to return to their mountain strongholds in Base Area 114 and through Charlie Ridge into Happy Valley.