Chapter 5 The Third Indochina War: The First Half-Year
As the post-cease-fire flurry subsided, activities in the four military regions began to develop patterns that persisted through the summer of 1973. As has been said so many times, there were four wars in South Vietnam, a different one in each military region.
In Military Region 1 both sides avoided serious contact as the NVA continued to consolidate and defend its positions and to construct its major logistical bases in northern Quang Tri and western Thua Thien Province. The South Vietnamese meanwhile used artillery sparingly and air power not at all in defending military posts and lines of communication along the coast.
In Military Region 2 the opposing sides developed strong positions around Kontum City. While the ARVN sought to keep NVA forces out of rocket range of the city and its airfield and to keep open Route 14 south to Pleiku, the NVA's new 10th Division pressed against the city's defenses to the north and west. Another area of contention developed around the westernmost ARVN outposts of Plei Mrong and Plei Djereng. The latter was destined not to survive because it was much too close to Duc Co, the major NVA logistical base in the highlands. The Communists also worked to improve their north-south logistical route from the vicinity of Dak To southward through the Plei Trap Valley of western Kontum Province. Combat in the eastern part of MR 2 centered primarily in Binh Dinh Province, where the NVA constantly harassed South Vietnamese posts, in the populated areas and along lines of communication. The ARVN responded with sorties into NVA areas in order to deny the enemy easy access to the coastal lowlands.
In Military Region 3 the NVA concentrated against Tong Le Chon, an isolated ARVN post deep in Communist-controlled northern Tay Ninh Province, located close to the Song Saigon, where the river was still a quiet stream winding through dense jungle on its way to the South China Sea. Existence of the post had forced the enemy to detour from preferred logistical corridors from Tay Ninh into Binh Long Province and southward along the Saigon River to Binh Duong. The NVA in March 1973 began a siege of the post destined to last for a full year. Although action elsewhere in the region was relatively light, harassment of outlying hamlets and resettlement areas was constant.
In Military Region 4 the heaviest action centered in the Seven Mountains area of Chau Doc Province, where ARVN Rangers were undertaking a slow and costly campaign to destroy the remaining elements of the NVA's 1st Division in that mountain stronghold. Other intense combat occurred in the Hong Ngu region along the border close to where the Mekong River enters South Vietnam from Cambodia. The rest of the region experienced relatively persistent harassment of Regional and Popular Forces outposts and of populated areas.
Relying on information supplied by the RVNAF Joint General Staff (JGS), DAO Saigon began reporting statistical and descriptive information on cease-fire violations. Arbitrary definitions were established in order to categorize hostile action. For example, a "minor attack by fire" was one in which 20 or fewer high explosive rounds hit a friendly position or populated area and in which casualties were five or less. For attacks of more than 20 rounds or five casualties, the category was a "major attack by fire." Contacts between ground troops were similarly defined as "minor" if ARVN casualties did not exceed five; as "major," if casualties were six or more. RVNAF ground operations resulting in combat were not reported as South Vietnamese cease-fire violations. The attitude taken by reporting officials in the JGS seemed to be that the RVNAF had the right to be in the particular area in which the conflict took place, and any resulting firefight was a violation attributed to enemy encroachment on South Vietnamese territory. Similarly, RVNAF artillery firings into suspected or known enemy locations were not reported as violations. The rationale was that the firing was defensive and in response to a clear threat or to a prior violation by Communist forces. Even though a certain amount of distortion thus crept into the reporting system and inaccuracies were doubtless present, the statistics on cease-fire violations provided a general idea of trends and patterns.
A look at Military Region 1 reports, probably the most accurate of those submitted from the field, shows a pattern of minor activity so characteristic of I Corps. In the three weeks immediately following the cease-fire, during the final phase of LANDGRAB 73, there were 58 major contacts between opposing forces, but in the fourth week, 18-24 February 1973, there were only 3. In the 20 weeks from 18 February until 5 July 1973, the weekly average for major contacts in the region was only 1.25. Minor contacts were also at the lowest level in the country, with 517 reported between the start of the cease-fire and 17 February. After that date a downward trend began, so that by the first week of July, the rate was down to 20 per week. The total in the 20-week period was only 1,107, a weekly average of SS.
The record in Military Region 1 becomes remarkable when compared with other regions, particularly the delta. Over 800 minor contacts occurred in Military Region 4 in the three weeks following the cease-fire. By July, the weekly rate was still in the 90's; the total for the 20 week period was 2,652, for a weekly average of over 130. Major contacts also maintained a high level in the delta; during the same period, the average was over 5.3 per week.
Casualties naturally followed a similar trend. In the three weeks following the cease-fire, about 500 ARVN soldiers died in combat in MR 1, compared to about 300 in the delta. The casualties then began to taper off in MR 1 until by July only 15 to 20 were killed in action each week, while the rate remained high in MR 4 with a weekly total of 80 or more.
The frequency of ground combat in Military Region 2 was between the low of MR 1 and the high experienced in the delta. Three weeks after the cease-fire and up until 5 July, the average frequency of major contacts had fallen to 3.25 per week; the number of minor contacts during this period was 1,205, an average of 60 per week. III Corps forces had more minor contacts (1,341), but major contacts were at the same low level as in MR 1, 1.25 per week.
The record of attacks by fire was also illustrative of the general situation and reflected the order of battle and the diversity among the four regions. In the delta, for example, enemy attacks by fire were frequent, though the rate remained fairly constant for the first five months after the cease-fire. This high rate reflected the large number of isolated outposts manned by South Vietnamese territorials which seemed to draw fire as candle flames attract moths. Since ARVN artillery was deployed throughout the delta, the customary response to an enemy mortar or rocket attack (the enemy had no field guns or howitzers in the delta), was counterbattery fire. From the cease-fire to 5 July, the JGS reported over 3,900 attacks by fire in Military Region 4, 46 percent of the country-wide total. ARVN artillery expenditures, partly in response to enemy fire, also remained fairly constant after the cease-fire, except for the first three weeks when South Vietnamese gunners fired about 190,000 rounds (105-mm. and 155-mm. howitzer). By the first week in July, IV Corps forces in the delta had expended almost 555,000 rounds, a modest 21 percent of the country-wide total.
By disregarding the first three weeks of the ceasefire, when expenditures were extremely heavy in Military Region 1, a more meaningful representation of ammunition usage appears. Over 25 percent of the artillery ammunition used after 17 February was fired in the delta. The consistency of the delta war is even more dramatically shown by ammunition figures after 29 April, when the heavy expenditures in MR 1 were sharply reduced. About one-third of the ammunition fired from 29 April to 5 July was expended in the delta.
As alluded to earlier, the high level of combat during LANDGRAB 73 in MR 1 was revealed in the statistics on attacks by fire and ammunition expenditure. In the first three weeks following the ceasefire, more than 46 percent of the enemy's attacks by fire were directed at targets in MR 1. Although the rate remained fairly high (second in the country) for the rest of the period, the share of attacks by fire in the region's I Corps had dropped by 5 July to 30 percent. A much more striking decline occurred in RVNAF artillery usage; in the three weeks following the cease-fire, nearly 670,000 rounds were fired by I Corps forces, almost 50 percent of the country total; but after 29 April, I Corps' ammunition usage accounted for only 18 percent of that fired country wide.
Attacks by fire in Military Region 2 were the lowest in the country. During the period under discussion, only 800 attacks by fire were directed at II Corps forces in the region, 9 percent of the total; 20 percent of these were launched in the first three weeks of the cease-fire. Ammunition usage was also the lowest, 430,000 rounds, or 16 percent of the total. This percentage would have been even lower had it not been for the heavy fires in support of attempts to retake Polei Krong and Trung Nghia in western Kontum Province in June. ARVN artillery fired 62,000 rounds in the four weeks of this action.
Attacks by fire in Military Region 3 were also relatively low, only 15 percent of the country total. Ammunition expenditures reflected that figure: 450,000 rounds for the period, or about 17 percent of the total. During a brief two-week period, (3-15 June), however, the region's gunners fired 87,000 rounds supporting an unsuccessful attack to open Route 13 from Lai Khe to Chon Thanh. This represented 57 percent of the shells fired from 29 April to 5 July.
The Threat to Saigon
The attempt in June 1973 to open Route 13 was symptomatic of a strategic malady from which the ARVN in Military Region 3 suffered throughout the months following the Nguyen Hue offensive up until the final capitulation. In an attempt to get more depth in the defense, the ARVN had maintained positions and outposts deep in territories which, if not under firm enemy control, were nevertheless subject to easy enemy interdiction with minimum forces. In strong positions guarding the western, northern, and eastern approaches to Saigon, the ARVN held in good order and in strength sufficient to repel any enemy offensive, assuming no significant reinforcement of Communist forces. The southern approaches were adequately protected by the dispositions of IV Corps around My Tho, and no sizable threat could develop in the Rung Sat, the extensive mud and mangrove delta of the Saigon and Dong Nai Rivers.
The defensive arc was nevertheless quite close to the capital. In the northwestern sector at Cu Chi the 25th ARVN Division was only 25 kilometers from Tan Son Nhut airbase. Although only one regiment was usually kept in the Cu Chi area, substantial territorial forces gave density and depth to the defenses there. Since this was perhaps the most likely approach to Saigon for armor, extensive antitank ditches were dug near strong points. The 25th kept one regiment at Tay Ninh West and the other in the Khiem Hanh-Tri Tam-Boi Loi triangle. Although inside contested territory, these dispositions afforded essential depth to the defense. The trouble was that the enemy often exercised his capability to interdict the tenuously held routes to the outposts, so that major operations were frequently required to run the resupply convoys, and increasingly heavy burdens were placed on aerial resupply.
The enemy crowded the ARVN defenses with local battalions, as well as main force regiments. Contact was virtually constant in the Ho Bo and Boi Loi areas north of Cu Chi, but an even more serious threat developed in the Long Nguyen, a heavily wooded, long-time enemy base area in the gap between Cu Chi and the 5th ARVN Division at Lai Khe. The 9th NVA Division pushed into this area from its bases in the Michelin and Minh Thanh plantations and was soon threatening lightly held territorial positions on the northern leg of the so called Iron Triangle: Rach Bap, Base 82, and An Dien.
An appreciation of the seriousness with which an enemy salient in the Iron Triangle had to be viewed can be gained from the following: First, the southern vertex of the Triangle, opposite the village of Phu Hoa and at the confluence of the Saigon and Thi Thien Rivers, is only 26,500 meters from the runways of Tan Son Nhut and Bien Hoa airbases, and maximum range of the 1 30-mm. field gun is 26,700 meters. Second, a successful crossing of the Thi Thien River below Ben Cat would isolate the 5th Division at Lai Khe, probably result in eliminating the defenses in front of the Binh Duong Province seat at Phu Cuong, and place enemy forces in a position for a rapid move into Saigon.
The lack of contiguous depth to the defense was much more apparent and had more immediate and serious consequences in the center sector where the NVA in the Nguyen Hue offensive had taken Loc Ninh, the district town north of the Binh Long Province seat of An Loc. Although the garrison at An Loc withstood the siege, destroying dozens of tanks and entire battalions in the process, eliminating the immediate threat to Binh Duong Province and Saigon, and providing a much needed psychological boost, the South Vietnamese were left with a large, critical base that could be supplied only by helicopter.
A similar problem existed southwest of the An Loc perimeter where at Tong Le Chon the enemy's siege by 25 March had begun in earnest. Soon after that date all resupply had to be parachuted, evacuation became almost impossible, and bombardment was almost continuous. Helicopters could not land without prohibitive risk, and the NVA antiaircraft positions around the camp became so dense that even approach by helicopter became almost impossible. In a 16-week period beginning on 25 March, the NVA conducted almost 300 attacks by fire against the camp, expending over 13,000 mortar, rocket, and artillery rounds. There were also 11 ground attacks and at least 9 attempts by sappers to infiltrate defenses. The NVA supported the attacks with psychological bombardments, promising over loud-speakers to afford the defenders safe passage out of the camp and appealing to the camp commander to lead his men out.
As of the first week in July, the total strength of the 92d Ranger Battalion inside the camp and two close-in outposts was 224 officers and men, of whom 34 were out of action because of wounds or illness. Total casualties for the period were 16 killed, 4 seriously wounded, and 192 lightly wounded or sick, including some with beri beri and malaria. Despite isolation and deteriorating morale, the ranger battalion nevertheless held fast and during those 16 weeks counted 86 enemy soldiers killed and 10 individual weapons captured, including an antiaircraft machine gun, and claimed destruction of one enemy 105-mm. howitzer.
During the 16-week period, the VNAF flew over 3,000 sorties supporting this little camp. The planes dropped more than three hundred 400-pound bundles of food and other supplies, of which 134 were recovered by the defenders while the remainder fell into enemy hands.
The besieging force consisted at first of a battalion of the 271st Regiment, 9th NVA Division, later replaced by a battalion of the 201st Independent NVA Regiment. Also included in the forces surrounding Tong Le Chon were a battalion each of the 42d and 271st NVA Antiaircraft Regiments of the 69th Artillery Group and firing batteries of the 28th NVA Artillery Battalion, the latter equipped with 130-mm. field guns.
South of the An Loc perimeter on National Route 13, was another isolated garrison at Chon Thanh Although regiments of the 5th ARVN Division were rotated in and out of Chon Thanh, the basic defense was the responsibility of territorials and rangers. A sortie out of the camp in early June by the 7th Infantry, 5th ARVN Division, progressed only five or six kilometers before being stopped with moderate casualties. This was an unsuccessful attempt to link up with the 8th Infantry attacking north out of the advanced base at Bau Bang, north of Lai Khe. Chon Thanh remained cut off for the rest of the war. An outpost at Chi Linh, southeast of the An Loc perimeter on the Song Be River, also required helicopter resupply.
Northeast of An Loc, a jungle-cloaked peak rises 700 meters out of the rolling woods, plantations, and farms of the Dong Nai terrace. Its beautiful, symmetrical cone shading Phuoc Binh, provincial seat of Phuoc Long Province, can be seen on clear days from Saigon. On some maps Phuoc Binh is labeled Song Be for the swift-flowing river that curves around the north base of the mountain. A military garrison was located at an airstrip near Phuoc Binh. This province headquarters was in no way integral to the defenses of Saigon; its importance was exclusively political in that throughout the war, the South Vietnamese could still claim possession of all province capitals.
Until the NVA Phuoc Long offensive of December 1974, Phuoc Binh could be reached by road from Kien Duc, in Quang Duc Province to the northeast, although the route was long and circuitous: from Nha Trang to Ban Me Thuot, thence to Gia Nghia and over to Kien Duc, then west to Phuoc Binh. Route 14 was kept open by troops posted at Duc Phong, about half the distance between Kien Duc and Phuoc Binh. Road travel was also possible with some risk south from Duc Phong to a small outpost at the Bunard plantation, but not beyond. The ARVN was unable to open Route 14 north of Don Luan (also known as Dong Xoai) after mid-March, although one convoy managed to get through an ambush on Route 1A and make it to Song Be. Even when interdictions of Route 1A south of the regimental base camp at Phuoc Vinh (called Phu Giao by the ARVN) became common, the ARVN managed to keep IA open to Phuoc Vinh most of the time, but not to Don Luan, which became totally dependent on aerial resupply.
The situation in the eastern sector was different, there being no isolated areas dependent on airlift for supply or evacuation and all major roads being open. Civilian and commercial as well as military traffic moved without escort on Route 20 to and from the mountain resort and gardens of Dalat. National Route 1 was open for all traffic to the coastal town of Phan Thiet, and Highway 15 was open to the beaches at Vung Tau. The 18th ARVN Division, with territorials in support, had no serious difficulties with the NVA's 33d and 274th Regiments in Long Khanh and Phuoc Tuy Provinces, although these main forces and some local Units made travel hazardous on Interprovincial Route 2 from Xuan Loc to Ba Ria. Constant patrolling was also necessary to protect traffic on Interprovincial Route 23 between Dat Do and Xuyen Moc in southern Phuoc Tuy.
The Cambodian Connection
The main ship channel of the great Mekong River empties into the South China Sea opposite the port city of Vung Tau. Convoys of tugs and barges for Phnom Penh marshalled there for the slow tow to Tam Chau, 150 miles up the brown river, just short of the crossing into Cambodia. All of the heavy tonnage comprising U.S. assistance to Cambodia - mostly ammunition, fuels, and rice - had to go this way since the Communists had closed off Phnom Penh from Cambodian ocean ports. The border areas of South Vietnam's Kien Phong, Chau Doc, and Kien Giang Provinces, as well as the southern reaches of the adjacent Cambodian Provinces of Prey Veng, Kandal, Takeo and Kampot, had long been used by the NVA and VC for base areas and lines of communication. The NVA in early 1973 had up to 11 regiments in Cambodia, all used in South Vietnam except for 3 or 4 deployed against Cambodian Government forces.
The situation that developed in this border area was unique and was due to the interaction of a number of factors: American efforts to keep the convoys moving; the NVA's attempts to stop them; the ARVN's support of the convoy effort as well as its determination to prevent Communist main force incursions and infiltration of supplies and men into Vietnam; the NVA's persistent commitment to keep the lines of communication open through Cambodia into South Vietnam; and finally, the peculiar harassment the Cambodian Communist units inflicted on the supply lines and depots of their NVA allies. While this last factor appeared to have little lasting effect on NVA effectiveness in South Vietnam, there was evidence of serious incidents which doubtless required the NVA to divert troops that could otherwise have been devoted to more productive activity.
The river town of Hong Ngu, where the Hong Ngu tributary flows into the Mekong, became the focal point of the NVA's attacks to clear impedments to infiltration and interdict the Mekong convoys as they moored at the Vietnamese Navy Base of Tan Chau before churning on into Cambodia. In March, the NVA concentrated above Hong Ngu in Cambodia the 207th Regiment, 6th NVA Division; the 174th Regiment, 5th NVA Division; the 272d Regiment (detached from the 9th NVA Division, which remained in the area of Minh Thanh and Michelin plantation of South Vietnam's Military Region 3); and elements of the 75th Artillery Group. With the 207th leading, supported by artillery, the North Vietnamese attacked from Prey Veng Province, Cambodia - NVA base area 704 - toward Hong Ngu. Not only did they meet immediate heavy resistance, but their rear area was pounded by B-52's and tactical bombers. The U.S. air effort in support of the Cambodian campaign to clear the Mekong banks from the Vietnam border to Phnom Penh was in full swing.
Benefits to the ARVN defense of Hong Ngu and Tan Chau were substantial. Several reliable reports told of heavy casualties and damage to the NVA's storage areas. One B-52 strike on 23 April 1973 north of the border between the Mekong and the Hong Ngu stream probably caught a large portion of the attacking force. Survivors reported seeing impressed civilians carrying the bodies of more than 100 NVA soldiers from the area. Many bunkers were destroyed, and the scent of death was heavy in the air.
In mid-April, the ARVN Infantry, 9th Division, together with the 2d Armored Cavalry Squadron and a Regional Forces Group, counterattacked. Although casualties were heavy, excellent VNAF and Vietnamese Navy support helped enable the ARVN troops to clear the east bank of the Mekong from Hong Ngu to the Cambodian frontier. Not only was control of this stretch of the river never again seriously threatened, but also the thrust inflicted heavy casualties and dealt a damaging blow to enemy morale. By the end of May, one battalion of the 207th NVA Regiment had only 100 men. By the 4th of May, when the Hong Ngu fighting had wound down to intermittent small contacts and light shellings, 422 enemy dead had been counted, while ARVN casualties were 94 killed, 743 wounded, and 36 missing.
Civilian casualties in the action were by far the highest since the cease-fire, over 300, of which 80 were killed by NVA artillery. Almost 300 houses were destroyed by enemy fire. In the second week of April alone 123 high-explosive 122-mm. rockets slammed into Hong Ngu.
Sparring in the Highlands
The situation in regard to isolated outposts was much the same in Military Region 2 as in Military Region 3. There was a deep but fragile arc of outposts manned by ranger border defense battalions and territorials extending north from Kontum City, and one isolated border camp, Plei Djereng, west of Pleiku. All had to be supplied by air.
Mang Buc, just inside Kontum Province on the border with Quang Ngai Province, was north of Kontum with no usable road in-between. Southwest of Mang Buc, over ridges rising to 2,100 meters, was Dak To, the only remaining position along Route 14 north of Kontum still held by the RVNAF, and Dak To itself was of little concern to the North Vietnamese because they were building a new highway that would bypass the camp on the west. South of Mang Buc and northeast of Kontum was the isolated camp of Chuong Nghia (also known as Plateau Gi). It too posed no particular problem for the North Vietnamese since they built a road bypassing it.
West of Pleiku, on the slopes of the high plateau above the valley of the Se San River, was Camp Le Minh at the village of Plei Djereng. This post posed a different problem for the NVA. It was on the edge of a base area being expanded from Duc Co. It was also on Route 509 leading directly to Pleiku. And it was astride the Route 14 complex that was under construction and would eventually link Khe Sanh in Quang Tri Province with the Bu Dop-Loc Ninh logistical center north of Saigon. For the ARVN the problem was familiar: only a major operation could open Route 509 from Pleiku to Plei Djereng, and the forces for that were not available. Thus Le Minh had to be supplied by air.
The most important ARVN tasks in the Kontum Pleiku defense were to keep the enemy from closing Highway 14 between the two cities, prevent NVA artillery from interdicting Pleiku Air Base or hitting the military logistical centers in the area, and keep Highway 14 open to Ban Me Thuot and Highway 19 open through the Mang Yang Pass. The western trace of the defense, which left much of the terrain uncovered, was anchored in Thanh An District on Highway 19 about midway between the junction of Highways 19 and 14 and the NVA's base at Duc Co. From Thanh An, the trace went north bending in toward Highway 14.
The forward positions west of Kontum were just east of Polei Krong and the adjacent village of Trung Nghia near the confluence of the Dak Bla and Krong Poko rivers. The NVA had attacked Polei Krong and Trung Nghia during the cease-fire landgrab and still occupied Polei Krong, which it appeared determined to hold, not only to provide a good point of departure for an attack on Kontum but also because Polei Krong was astride one of the best north-south lines of communication. This area became the scene of some of the heaviest fighting in Military Region 2 during the summer and early autumn of 1973. Southwest of Kontum, on Three Points Mountain (Hill 700) overlooking Provincial Route 3B and the Dak Bla River, was the isolated outpost of Doi Ba Cham, accessible only by helicopter.
In mid-May, VNAF aerial observers saw two 130-mm. guns being moved into position northwest of Kontum. Primarily through agent reports, ARVN intelligence officers learned of NVA plans to use artillery against ARVN artillery batteries in the Kontum City area. Shortly afterwards, heavy attacks by fire hit the ARVN fire bases and positions of the 53d Infantry Regiment, 23d ARVN Division, northwest of the city on Eo Gio Hill and Bases N and R. Two NVA ground attacks against Doi Ba Cham were repulsed. Artillery bombardments by the NVA's 40th Artillery Regiment, employing 130-mm. gun and 122-mm. rocket fire, continued against forward ARVN positions and artillery batteries during the first week of June, while elements of the 10th NVA Division conducted ground probes against three forward ARVN positions. On 7 June, a major attack by battalions of the 66th Regiment, 10th NVA Division, and the 24th Independent NVA Regiment, supported by at least 10 T-54 tanks and by fire from 130-mm. guns and 122-mm. rockets, struck ARVN positions at Trung Nghia and Polei Krong. The attack drove a regional force battalion and elements of the 44th ARVN Regiment from their positions, affording the NVA control of positions 17 kilometers west of Kontum City.
Even as the 10th NVA Division was pressing hard against the Kontum perimeter, the 320th NVA Division was trying to force contraction of the ARVN defenses west of Pleiku as well as those protecting Highway 14 north of the city. In early May, ARVN intelligence learned that at least one battalion of the 95-B Regiment, 10th NVA Division, had moved out of the Chu Pao Pass area and into a base near Plei Monoun, just south of the Yali Falls, there to prepare for attacks on the ARVN ranger base at Plei Mrong.
In late March a more serious situation was developing in Thanh An district on Highway 19 where elements of the 320th Division began moving from Duc Co toward the ARVN base at Thanh Giao. In the first week of April, the defenders were pounded by 18 separate bombardments and beat off five major ground attacks, although an outer defense perimeter was forced to pull back. Examination of shell fragments disclosed the presence of 130-mm. guns and 120-mm. mortars. It was obvious that the NVA wanted more buffer space east of Duc Co. VNAF's aerial observers saw a new compound of 34 buildings being erected near the airfield, and photos disclosed extensive new road construction. VNAF bombers attacked a crossing on the Se San River, which forms the Cambodian border at this point, and destroyed 13 medium ferries while ARVN's aggressive defense at Thanh Giao caused the NVA to back off for a few weeks.
By 1 May the 320th Division's 64th Regiment was bivouacked north of Thanh Giao and the 48th remained to the south. Nevertheless, no significant attacks took place, and the ARVN 47th Regiment, 22d Division, having moved from Binh Dinh Province, stiffened the defenses in Thanh An District.
The RVNAF II Corps Commander, Maj. Gen. Nguyen Van Toan, could deploy the 47th Regiment to reinforce Pleiku with confidence that the 22d Division could control the situation in Binh Dinh without it. Over a year having passed since the 22d was badly mauled in Kontum, the division was well on the way to recovery. In northern Binh Dinh the division nibbled at enclaves seized by the Communists in January, finding that the NVA 3d Division was barely effective. The 12th NVA Regiment was in western Tam Quan District, and the 2d and 21st Regiments had pulled out of Hoai Nhon to refit and receive replacements west of the An Lao River in Hoai An District. The fighting strength of the enemy battalions was probably under 200 men each. Having lost heavily in LANDGRAB 73 and in postcease-fire engagements, the division's morale, as well as its strength, was at a low point, while the ARVN 22d Division was gaining strength and appeared to be imbued with the confidence and drive of its commander, Brig. Gen. Phan Dinh Niem. In any event, with the 6th Ranger Group operating in Tam Quan District, the 40th and 42d Regiments in Hoai Nhon, and the 41st Regiment in Phu My, the 22d ARVN Division as mid-summer approached controlled the main lines of communication and populated coastal regions of Binh Dinh Province.
The South Vietnamese outnumbered the NVA and VC forces in Military Region 2. The ARVN 22d and 23d Divisions had a total of seven regiments in Binh Dinh, Kontum, and Pleiku Province. There were also the 2d Ranger Group, detached from III Corps, and battalions of the 7th Rangers from IV Corps. In all there were 18 Ranger battalions in MR 2 in the summer of 1973. On the other side of the ledger, the enemy had his 3d, 10th, and 320th Divisions, the first two with three regiments and the third with two. The NVA also had four separate regiments and as many as 40 understrength independent battalions but total enemy combat strength in MR 2 was probably under 30,000. The NVA nevertheless demonstrated at Trung Nhia and Polei Krong an ability to concentrate the forces required at a vulnerable objective to achieve temporary success. On the other hand, the enemy failed to concentrate against any decisive objectives in Pleiku or Binh Dinh Provinces, even though the RVNAF was spread thinly throughout the corps area. The activity in MR 2 during the early summer of 1973 illustrated a perennial truth about main force combat success and failure in Vietnam: despite overall numerical and qualitative inferiority, the NVA could concentrate forces, achieve temporary fire and maneuver superiority, attack with some degree of tactical surprise, and overwhelm local RVNAF defenses.
Logistics and Infiltration
By the end of June, at least three NVA transportation regiments were moving supplies along the northern section of Highway 14 from the Khe Sanh area into the A Shau Valley. At least three major storage depots were moved out of Laos into South Vietnam, probably to be located in the new Highway 14 area. As much as 10,000 short tons of supplies were moved into the B-3 front and NVA Military Region 4 during June. This amount was evidently part of the estimated 50,000 short tons which crossed the DMZ into Quang Tri during the first weeks after the cease-fire. The Highway 14 network inside South Vietnam would, when completed, provide an alternate to much of the Ho Chi Minh Trail in Laos. Significantly, when the roads in the southern Laos panhandle were washed out in the southwest monsoon, the Route 14 net in the northern highlands of South Vietnam would be dry and trafficable.
Enemy logistical developments received close attention at DAO and by the J2 of RVNAF. A competent intelligence estimate, employing conservative criteria, concluded that as of the end of May 1973, the NVA had moved supplies into Laos and South Vietnam in sufficient quantities to support offensive operations in South Vietnam at the 1972 (31 March 72 - January 73) level for 13 to 18 months and that these supplies would be sufficient to begin a similar offensive by July 1973. Replacements, however, had not yet been received in the numbers required to bring combat units up to the strengths preferred by the NVA for launching an offensive.
From January through June, 65,000 replacements arrived in South Vietnam. This compared to over 92,000 during the same period of 1972. Even when reassigned ex-prisoners of war were added to the totals, a picture of understrength enemy units remained. The RVNAF JGS had estimated enemy casualties during 1972, killed, permanently disabled, or died of wounds, at over 178,000. Even if generous adjustments were made for possible exaggerations, there was no question but that losses were extremely heavy and an estimated 39,000 more enemy soldiers were permanently put out of action during the first six months of 1973. Thus the enemy still had some catching up to do in regard to replacements (RVNAF losses were also heavy in 1972 with over 40,000 killed. Although much lower than those incurred during the Nguyen Hue offensive, casualties in the first half of 1973 were substantial: 15,800 killed, 5,000 dead from non-combat causes, 73,700 wounded in action, and 16,000 injured from noncombat causes.)
Guns and tanks were also moving south. A reasonable estimate, proved accurate by information acquired subsequently, was that the NVA had brought about 140 new 122-mm. and 130-mm. guns into South Vietnam since January 1973, and that about half of these went to COSVN with the rest to Military Region 5 and the B-3 Front. About 250 new tanks also entered the country, also going to COSVN with smaller equal shares to the B-3 Front and MR 5.
The SA-7 "Strella"
Amid the remarkable increase in NVA antiaircraft strength in South Vietnam the gravest threat to VNAF planes, particularly in the southern part of the country, was the SA-7 hand-held missile. From the cease-fire until the end of June, there were 22 reported SA-7 attacks on VNAF aircraft, 8 of which shot down the planes. The following tabulation gives the date / province / aircraft and result:
4 Feb / Quang Tri / A-37, destroyed 25 Feb / Dinh Tuong / UH-1H, missed 3 Mar /Dinh Tuong / A-1H, missed 3 Mar / Dinh Tuong / AC-119, missed 3 Mar / Binh Duong / UH-1, missed 6 Mar / Dinh Tuollg / UH-1, missed 20 Mar / Dinh Tuong / A-37, missed 23 Mar / Tay Ninh / CH-47, missed 24 Mar / An Xuyen / UH-1, missed 28 Mar / Binh Long / A-1H, destroyed, pilot missing 28 Mar / Binh Long / AC-119, missed 29 Mar / Binh Long / A-1H, destroyed, pilot missing 29 Mar / Binh Long / F-SA, destroyed, pilot missing 7 Apr / Quang Tri / UH-1 (ICCS), destroyed, 7 killed 16 Apr / Tay Ninh / L-19, missed 20 Apr / Kien Phong / A-1G, destroyed 20 Apr / Kien Hoa / UH-1, destroyed, 1 killed, 3 wounded 29 Apr / Kien Phong / L-19, missed 30 Apr / Kien Phong / L-19, missed 8 May / Tay Ninh / UH-1H, missed 3 Jun / Tay Ninh / CH-47, destroyed, 5 killed 25 Jun / Tay Ninh / UH-1H (two), missed
The concentration of firings and successful attacks in Binh Long Province reflected the intensity of the VNAF air support provided during the effort to relieve the siege of Tong Le Chon. The rather low ratio of successful firings - slightly better than one out of three - was attributable in large degree to effective countermeasures adopted by the VNAF. As the SA-7 was fired, it had a distinctive flash which could often be seen from the air, followed by a characteristic smoke and vapor trail. With attack aircraft flying in pairs, one or the other of the pilots might see the missile coming and take or direct evasive action. High-energy flares were sometimes tossed out or mechanically ejected, frequently causing the missile's heat-seeker to lock on and track the flare and burst a harmless distance from the plane. Helicopter crews were also alert to watch for missiles, and in order to reduce infrared emissions, UHI helicopters were modified. The hot-spot on the fuselage below the main rotor was shielded and theexhaust diverted upwards by means of an elbow attached to the tailpipe. But regardless of these moderately effective measures, the result of this contest between air and ground was an environment that forced reconnaissance and attack aircraft above optimum operating altitudes and virtually eliminated the employment of large helicopter formations.
As the NVA was preparing for the assault on Trung Nghia in Kontum, as NVA regiments were making their futile but bloody attempts to continue the attack out of Cambodia into Hong Ngu, and as the ring was being drawn ever more tightly around Tong Le Chon, the diplomats were meeting again in Paris to assert once more the desire of all parties for a real cease-fire and a lasting peace in Vietnam. The communiqué that issued from the conference marked the beginning of a period which in Saigon was called "Cease-fire II."
Note on Sources
Statistical information on cease-fire violations was principally derived from DAO Saigon Quarterly Assessments, March and June, 1973. The RVNAF/JGS reports on this subject were the primary source used by DAO in publishing its Quarterly Assessments. The general situation prevailing in the country during this period was described with reference to DIA, DAO, Saigon, U.S. Embassy and J2/JGS reports, studies, and assessments. Particularly helpful in this regard were the contributions of Gen. Phan Dinh Niem, commander of the ARVN 22d Infantry Division, who filled in many blanks and corrected some erroneous data concerning the activities and deployment of his division and other forces in the highlands and in Binh Dinh.