Battle
1974 military engagement of the Vietnam War
The Battle of the Iron Triangle took place from 16 May to 20 November 1974, when the People's Army of Vietnam (PAVN) 9th Division captured Rach Bap and An Dien. The Army of the Republic of Vietnam (ARVN) regained the lost towns in a series of costly counterattacks.
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Text from the Wikipedia article “Battle of the Iron Triangle”, available under CC BY-SA 4.0.
The Battle of the Iron Triangle took place from 16 May to 20 November 1974, when the People's Army of Vietnam (PAVN) 9th Division captured Rach Bap and An Dien. The Army of the Republic of Vietnam (ARVN) regained the lost towns in a series of costly counterattacks.
The Iron Triangle was an important strategic location, bounded on the north by the jungle and overgrown rubber plantations of the Long Nguyen Secret Zone, on the west by the Saigon River and on the east by the smaller but unfordable obstacle of the Thi Thinh River. Phú Cường, the capital of Bình Dương Province, was an important industrial and farming center and contained the ARVN Engineer School. It was linked by a major highway with the large ARVN Phu Loi Base Camp and, farther east, with Bien Hoa Air Base. Lying as it did in the center of the Saigon River corridor, at the junction of Highways 13 and 1, and only 16 km from the outskirts of Saigon, Phú Cường was vital to the defense of Saigon.
The terrain within the Iron Triangle was flat, almost featureless, and covered by dense brush and undergrowth. The clearings, especially in the northern part, were thick with elephant grass, higher than a man's head. The surface was scarred by countless bomb and shell craters so that vehicular movement off the narrow, rough dirt roads was nearly impossible; even tracked vehicles had difficulty. A vast network of tunnels and trenches, most of them caved-in and abandoned, laced this ground that had been the scene of battles since the First Indochina War.
A weak string of three ARVN outposts protected the northern edge of the Triangle, from Rach Bap (11°07′43″N 106°30′58″E / 11.1287°N 106.516°E) on the west, close by the Saigon River, along local Route 7 to An Dien (11°08′53″N 106°35′10″E / 11.148°N 106.586°E) on the Thi Thinh River opposite Bến Cát. Each of these outposts, including Base 82 (11°07′59″N 106°32′38″E / 11.133°N 106.544°E), which was midway between Rach Bap and An Dien, was manned by a company of the 321st Regional Force (RF) Battalion. Another country road passed by the Rach Bap outpost, local Route 14, which generally paralleled the Saigon River from Tri Tam, through Rach Bap, and veered to the southeast through the Triangle, crossing the Thi Thinh River before it joined Highway 13 north of Phú Cường. The PAVN had blown the bridge on Route 14 over the Thi Thinh a few weeks earlier, but the stream could be spanned by pontoon sections. About midway between Rach Bap and the Thi Thinh crossing of Route 14, the ARVN had another small firebase.
Frequent sweeps and some semi-fixed defensive positions north of Củ Chi manned by the ARVN 25th Division and Hậu Nghĩa Province RF screened the western flank of the Triangle, but PAVN resistance in the Ho Bo Woods opposite Rach Bap and the formidable obstacle of the Saigon River, as well as a lack of resources, limited the influence that the 25th could exert on the situation within the Triangle. The ARVN was strong with infantry, armor, and mutually supporting fire bases and outposts in Bến Cát District east of the Thi Thinh boundary of the Triangle, but only one bridge, a weak span, connected the district town and the Triangle hamlet of An Dien.
On 16 May the PAVN 9th Division began their attack on with heavy artillery, rocket, and mortar concentrations falling on Rach Bap, Base 82 and An Dien. The RF company at Base 82 abandoned its bunkers, many of which had collapsed under the weight of the bombardment, late that afternoon. Rach Bap held out until about 03:00 on 17 May, its surviving defenders withdrawing in the direction of An Dien. The fighting was fierce in An Dien on the 16th, but by the night of 17 May, PAVN forces held the flattened village and its defenses. Remnants of an RF battalion, however, held the western end of the Thi Thinh bridge in a shallow blocking position, while the eastern end, by Bến Cát, was secured by ARVN forces. The PAVN dug in around An Dien but was unable to dislodge the RF positions at the bridge. Two infantry regiments of the 9th Division, with about 10 T-54 and PT-76 tanks, were employed against the dispersed 321st RF Battalion. The 2nd Regiment overran Rach Bap and continued the attack south into the Triangle along Route 14, while the 95C Regiment attacked Base 82 and An Dien. The 271st Regiment was held in reserve.
The ARVN at Ben Cat were unable to counterattack the PAVN immediately at An Dien because the bridgehead held by the RF was too shallow to protect the crossing of any large forces, but III Corps commander Lieutenant general Phạm Quốc Thuần quickly began reinforcing Bến Cát. Task Force 318 arrived in Bến Cát on the afternoon of the 16th and on the 17th began reinforcing the RF holding the bridge and moving against the PAVN's blocking positions west of the bridgehead. The weakness of the ARVN bridgehead and the strength of the enemy positions in An Dien, which included antitank guns and tanks, made it impractical to send any armor of the 318th across the An Dien bridge at this time.
Meanwhile, the 322nd Task Force moved from Tây Ninh Province to Phú Cường and was ordered to prepare to attack into the Triangle along Route 14 in order to oppose the PAVN 2nd Regiment, which was moving south from Rach Rap. Republic of Vietnam Air Force (RVNAF) aerial observers and photography on 17 May revealed two T-54 tanks inside Base 82, which RVNAF fighter-bombers destroyed the next day, and four more in the An Dien base. Initial negative reactions at III Corps Headquarters to the seemingly hasty, if not unwarranted, withdrawal of the RF companies from their positions softened somewhat when the size and composition of the PAVN force was revealed.
Thuần greatly underestimated the strength and tenacity with which the PAVN 9th Division would defend An Dien, although he had accurate intelligence concerning the size, composition, and location of his enemy. His initial plans, which proved unrealistic, called for virtually simultaneous recapture of the three lost bases by about 22 May. Except for the few ARVN infantry and engineers that were thrown across the Thi Thinh River to reinforce the An Dien bridgehead, the first major ARVN unit to move into the Triangle was a battalion of the 43rd Infantry Regiment, 18th Division, which crossed on Route 14 north of Phú Cường. Shortly reinforced by the rest of the regiment, this element, followed by the 322nd Armored Task Force, was to attack Rach Bap and Base 82. Meanwhile, the 318th Task Force would cross the An Dien Bridge, pass through An Dien, and proceed to Base 82. Three Ranger battalions attacking south out of Lai Khê were to strike Base 82 from the north. None of this worked as planned. The 43rd Infantry became stalled after advancing only 4 or 5 km north. Then, the tracked vehicles of the 322nd Task Force found the going extremely slow in the dense brush and cratered terrain. Thuần, concerned that this armored force might become bogged down and have a bridge blown behind it ordered its withdrawal. He discovered, meanwhile, that the An Dien bridge had been seriously weakened by PAVN artillery (including AT-3 missiles) and would not support the tanks of the 318th Task Force. Under PAVN observation and sporadic heavy mortar and artillery fire, ARVN combat engineers attempted to repair the bridge. Casualties mounted, and the work progressed very slowly. About the same time, the 7th Ranger Group, with three battalions, moved southwest out of Lai Khê, crossed the Thi Thinh River and advanced on Base 82. The Rangers were immediately opposed in the thick jungle and rubber plantation by entrenched PAVN 9th Division troops, and their attack stalled well short of the objective.
While the ARVN was experiencing great difficulty advancing, it was pounding An Dien with heavy artillery fire. The North Vietnamese responded against ARVN batteries and the stalled Ranger and infantry columns and sent sappers into an RF command post just south of Bến Cát, where they destroyed a 105 mm howitzer and routed most of the small garrison. The RVNAF meanwhile, gave only limited support as plentiful PAVN antiaircraft artillery and SA-7s forced RVNAF aircraft to high altitudes. On 24 May an armored cavalry squadron of the 25th Division launched a diversionary attack from Gò Dầu Hạ east toward the Boi Loi Woods in an attempt to prevent the 9th Division from committing its reserve, the 271st Regiment, against either the 318th or the 322d Task Forces. By the 25th, the armored cavalry squadron had passed Suoi Cau without encountering any resistance, and another supporting maneuver began with two battalions of the 50th Infantry, 25th Division, moving north from Phú Hòa District along the west bank of the Saigon River.
On 25 May, Thuần met with the commander of the 18th Division, Brigadier general Lê Minh Đảo and the commander of the 3rd Armored Brigade, Brigadier general Trần Quang Khôi, to coordinate the following morning's attack. At that time, the 43rd Regiment was about 7 km south of An Dien, about to attack north, while the 3rd Armored Brigade was preparing to send a cavalry squadron and a Ranger battalion across the An Dien bridge. Although the PAVN's heavy mortar and artillery fire had so weakened the bridge at An Dien that the cavalry could not follow the Rangers, by nightfall the 64th Ranger Battalion was dug in on the eastern edge of An Dien Village. The 43rd Regiment was again ordered to resume the attack north, and the 7th Ranger Group, coming down from Lai Khe was ordered to take Base 82 by night attack on 27 May. Because no progress was made Thuần on 28 May decided to try a fresh approach. First he turned the operation over to Đảo, told him to move his 52nd Regiment over from Phú Giáo District, gave him operational command of the 7th Ranger Group, which was still north of Base 82, and attached to Đảo's 18th Division a reinforced squadron of the 3rd Armored Brigade. Since it would take two days to relieve the 52nd Regiment on the Phú Giáo front and move it into position at Bến Cát, the new operation was scheduled for 30 May. Delays in the relief and movement forced Đảo to move the date to 1 June.
With the Rangers still holding the shallow bridgehead opposite Bến Cát and the 43rd Regiment making slow progress attacking the dug-in PAVN 272nd Regiment south of An Dien. Đảo sent the 2nd Battalion, 52nd Regiment across the Thi Thinh River on an assault bridge south of Bến Cát on 1 June. Once across, it turned north to attack the defenses of the PAVN 95C Regiment in An Dien. Meanwhile, the reconnaissance company and an infantry company from the 18th Division crossed the An Dien bridge and advanced toward the village. Casualties on both sides were heavy as the commander of the 52nd Regiment committed his 1st Battalion behind the 2nd. The PAVN responded by assaulting the ARVN infantry that night with infantry and at least 10 tanks. The two battalions of the 52nd held their positions and were reinforced by the 3rd Battalion the next afternoon. Meanwhile, ARVN combat engineers were clearing the road past the An Dien bridge. Working at night with flash lights to avoid PAVN observation and fire, they removed 38 antitank mines from the route of advance.
Text from the Wikipedia article “Battle of the Iron Triangle”, available under CC BY-SA 4.0.