Annex A

a. On 29 April 1970, ARVN forces staging from Tay Ninh City and the vicinity of Go Dau Ha initiated Phase 1 of Toan Thang 42 in Cambodia, northwest of the Angel's Wing. (See Appendix 1). TF 318 attacked south from Tay Ninh concurrent with two task forces attacking from the vicinity of Go Dau Ha. TF 225 and TF 333 initially encountered heavy resistance while TF 318 along HWY 1 experienced light and sporadic enemy contact. US support during this phase included gunship coordinators, gunships command and control helicopters and artillery support.

b. During the period 2 - 6 May, III MR forces launched Phase II of Operation Toan Thang 42 in the Parrot's Beak of Cambodia in concert with three Combined Arms Teams from IV MR. (See Appendix 2). TF 225 and TF 333 attacked to the south from positions along HWY 1 while TF 318 secured HWY 1. Both task forces made heavy contact with enemy forces in newly prepared bunkers. On 3 May, TF 318 deployed forces to the west of Svay Rieng to assist Cambodian forces in the area. On 4 May, all elements began to reposition for a two-day maintenance standdown in preparation for the initiation of Phase III. On 5 May, three CIDG companies from Duc Hue and Tra Cu Special Forces Camps were deployed in the Parrot's Beak. During Phase II and subsequently until 30 June US support consisted of advisors, gunships, medevac, emergency resupply, and artillery. No support was rendered beyond the 30 kilometer limit.

c. Phase III began on 7 May with TF 225 attacking from Ben Soi, RVN, west along Highway 13 hile TF 318 and TF 333 attacked to the north from the vicinity of Prasot and Chipu. (See Appendix 3). By middy, TF 225 engaged and overran enemy forces several kilometers inside Cambodia while TF 333 encountered only light resistance. TF 318 encountered heavy opposition initially which resulted in slow progress. There were over 150 enemy killed in this contact. On 9 May, TF 225 discovered a field hospital complex containing 200 beds, an operating room, and a considerable amount of medical supplies. During this phase, CIDG elements and three companies from 6th Battalion, 31 Infantry, 3rd Bde, 9th Inf Div, were committed in the area of Parrot's Beak to prevent enemy reoccupation, to destroy remaining enemy forces and to search for enemy caches. The discovery of numerous caches in the area prompted the CG of III Corps to return one of his task forces to this area as part of Phase IV.

d. Phase IV, 13-22 May, began when TF 318 initiated operations to the west along HWY 1. (See Appendix 4). Forces moving astride HWY 1 linked up with the elements of IV Corps at Trabek, thus opening significant contact that resulted in 48 enemy killed and 56 enemy captured. Interrogation identified the D-1 LF Battalion of Tay Ninh Province. On 17 May, TF 225 operating south of HWY 1 in the Parrot's Beak as mentioned above, made contact with a large enemy force with 26 enemy killed and 20 prisoners. Interrogation identified this enemy unit as the 3rd Bn, 1st NVA Regiment. Two RF Inter-Company Groups assumed responsibility for securing HWY 1 between the border and Svay Rieng, releasing additional III Corps forces for mobile operations. On 20 May, elements of TF 333 made a heavy contact resulting in 9 enemy killed and 226 prisoners. Interrogation identified the 2nd Bn, 271st Regt, 9th VC Division. TF 225 continued operations in the area south of HWY 1 and on 21 May, a contact resulted in 12 enemy KIA and 15 captured. One of the prisoners was subsequently identified as the Deputy Commander of the Forward Supply Council of SR-3.

e. On the morning of 23 May, Phase V of Toan Thang 42 operations was initiated against enemy forces in the Chup Rubber plantation area. (See Appendix 5). TF 333 moved west from Krek on Highway 7 against stiff resistance. A heavy contact with the 1st Bn, 272nd Regiment resulted in 26 enemy KIA and 16 PW's, one of whom was identified as the Battalion Executive Officer. On 27 May, to the west of the Angel's Wing, the 216th RF Company engaged an enemy force from the 308th and D-16 Bns of SR-2, resulting in 31 enemy killed and 25 enemy captures. On 31 May, elements of the 706th RF Company operating in the southern portion of BA 706 killed 6 enemy and captured 14. In another contact on the 31st, elements of TF 225 operating west of the Angel's Wing killed 34 enemy and captured 2. Both prisoners were from the 308th Bn of SR-2. On 12 June, TF 318 moved to the vicinity of Krek, replacing a brigade of the 25th Inf Div. On the following day, TF 333 withdrew from Cambodia for standdown in Long Khanh and Bien Hoa Provinces. On 20 June TF 333 moved to Thien Ngon for subsequent deployment into Cambodia to assume the mission of TF 318 in the Krek area, releasing TF 318 to move west to conduct operations in the vicinity of the Chup Rubber Plantation. On 24 June, TF 318, reinforced with an additional combined arms team from TF 333, attacked south along Highway 15, with the mission of relieving enemy pressure around Prey Veng.

a. On 1 May, the 1st Cavalry Division (AM) initiated operation Toan Thang 43 in the southern Fishhook area comprising portions of Base Areas 352 and 353. The attacking forces consisted of the 3rd Brigade, 1st Cavalry Division (2/34 Armor and 2/47 Inf (Mech) from 25th Inf Div attached), 11th Armored Cavalry Regiment, and the 3rd Brigade, ARVN Airborne Division. (See Appendix 6). The attack was preceded by B-52 strikes, followed by intensive tactical air strikes and an artillery preparation. Task Force Shoemaker was established on 30 April at Quan Loi as the control headquarters for the initial US cross-border operation. The 3rd Brigade, 1st Cavalry Division initially attacked to the northeast with two mechanized task forces as the 11th ACR attacked north into Base Area 352 with two squadrons. The 3rd Airborne Brigade committed three battalions into Base Area 352 by heliborne air assault while the 1st ARVN ACR moved west from the vicinity of An Loc to attack into the Fishhook across the Tonle Cham River. On 2 May the 1st ARVN ACR linked up with the eastern-most airborne battalion. 3rd Bde, 1st Cavalry Division, air assaulted an additional battalion to block along Route 79 and establish FSB X-Ray (SU 3501). Late in the afternoon of the 2nd, elements of the mechanized task force operating on the west flank cut Highway 7 east of Mimot.

b. The scope of operation was expanded as an additional airmobile battalion was air assaulted into the area west of the Flat Iron to exploit a cache site and to establish FSB North. On 5 May, Task Force Shoemaker was dissolved and 1st Cav Div HQ assumed direct control of the operation utilizing its 1st and 3rd Brigades, the 1st ARVN Abn Brigade, and the 11th ACR to control 13 committed maneuver battalions. On this day, the 11th ACR with two squadrons attacked north to Snual, seizing the town after a series of sharp skirmishes that resulted in 150 enemy killed. In the first five days of the operation, numerous enemy caches containing weapons, ammunition, vehicles, and food-stuffs were seized. At this point over 600 enemy soldiers had been eliminated and several large storage and training areas had been located. The period 6-9 May was marked by the exploitation of many cache sites to include a major enemy storage area (XU5321) directly west of the Flat Iron which was promptly dubbed, “The City.” Supporting engineers constructed a connecting road from Highway 13 to this area to facilitate overland evacuation of large quantities of weapons, material, and rice.

c. On 9 May the 2nd Brigade, 25th Infantry Division, with three battalions, attacked into Base Area 707 southwest of Mimot against light and scattered resistance. This attack was extended on 11 May to exploit six B-52 strikes against elements of COSVN headquarters in a suspected location northwest of Mimot, vicinity XU1515. (See Appendix 7). The 11th ACR moved south of Snuol to provide security of Route 13 and provide flank protection for the 9th ARVN Regiment operating in Base Area 350 as part of operation Toan Thang 46 (paragraph 5 below). Enemy contacts were generally light with some enemy attacks against fire bases and night defensive positions. The number of attacks by fire rose as the enemy showed signs of reorganization. Beginning in mid-May, enemy resistance stiffened north of Highway 7 and in the Fishhook area. On 14 May a battalion of the 1st Cav Div was withdrawn from the operations to reinforce operations in Base Area 351. On 14 May the 1st Brigade of the 25th Infantry Division relieved the 1st Brigade of the 1st Cav Div in the area west of the Fishhook. The ARVN Airborne Division assumed control of operations in the Fishhook committing two additional battalions and a second brigade HQ. (See Appendix 8). Enemy reaction to reconnaissance intensified at this time and attacks by fire increased in intensity and volume against the ARVN Airborne Division.

d. On 21 May the 1st Cav Div deployed a brigade HQ and one infantry battalion to the vicinity of O Rang, north of Bu Dop. Also on 21 May, a squadron of the 11th ACR returned to regimental control as the 25th Inf Div inserted an additional battalion in the vicinity of Mimot. On 27 May, the 1st Cav Div withdrew its remaining battalion from Base Area 352 and committed it north of Bu Dop. ARVN Airborne units continued to encounter stiff enemy resistance throughout their AO. Meanwhile, the 25th Inf Div discovered numerous small weapons and ammunition caches, plus several large rice caches north and west of the Mimot area. On 10 June the 2nd Brigade, 25th Infantry Division, began repositioning forces in RVN east of Base Area 354. Concurrently, ARVN III Corps units occupied the area west of Mimot and assumed a portion of the 25th Inf Div AO. On 14 June, the cavalry squadron of the 25th Infantry Division was placed in direct support of the ARVN Airborne Division as the division further expanded its area of operation into the area vacated by the 25th Infantry Division. The remaining elements of the 1st Bde, 25th Inf Div, moved back into RVN on 19 June. Concurrently, the 11th ACR (-) was placed OPCON to the division and tasked to secure land clearing operations.

e. On 4 June the 60th Land Clearing Company began tactical operations, clearing in the Fishhook region in conjunction with the 1st Squadron, 11th Armored Cavalry Regiment. On 14 June the 984th Land Clearing Company moved into an area south of the 60th. These two companies cleared 1,694 acres of heavy jungle and destroyed more than 800 heavily reinforced bunkers during the period through 26 June. Both companies encountered heavy enemy resistance, making 56 separate contacts during the time they were in the Fishhook.

f. Beginning 21 June, the ARVN Airborne Division began withdrawing elements of its 1st Brigade from the Fishhook area. Land clearing companies operating in the Fishhook terminated tactical cuts and completed withdrawal on 25 June. With the withdrawal of ground units from the Fishhook area, the 25th Infantry Division employed tactical air, B-52 strikes, air cavalry, and II FFV Artillery in an intensive effort to destroy enemy personnel, supplies, and facilities remaining in the area. Also during this period, CS-2 drops were conducted within Base Area 352 to temporarily deny enemy use of/or reoccupation of four key base complexes.

a. This operation was initiated on 6 May by the 1st Bde, 25th Infantry Division, employing four battalions in Base Area 354. The attack was preceded by tactical air strikes and an artillery preparation. One infantry battalion was combat assaulted into the center of the base area while one company of the battalion was inserted to secure a bridge site over the Rach Beng Go River (vic 968751). Two Commando Vault * devices were employed to prepare landing zones for those two assaults. Air Cavalry elements screened to the west and ranged throughout the objective area. Initial enemy contacts were light and scattered. A float bridge was installed to permit two mechanized battalions to attack into the interior of the base area. One mechanized battalion attacked to the east, linked up and passed through the airhead of the infantry battalion, vicinity WT9275. The second mechanized force crossed the bridge and swept south along the west bank of the Rach Beng Go River. Extensive search operations were then initiated in the area.

a. On 6 May the 1st Cav Div (AM) initiated its second cross-border operation. The 2nd Bde, 1st Cav Div, air assaulted two battalions into Base Area 351 northeast of Bu Dop. At the outset, enemy resistance was light and scattered. An early evening contact on 7 May led to the initial discovery on 8 May of a very large ammunition and weapons storage area which became known as “Rock Island East.” Supporting engineers had to open Route 14 so that overland evacuation of the captured material could be accomplished. Exploitation of this cache site required nine days. On 11 May an additional battalion of the 2nd Bde was inserted to the northwest of Bu Gia Map vicinity YU 1352. Tactical air and air cavalry elements were employed against small convoys of vehicles and daylight troop movements to the north of Base Area 351. A fourth infantry battalion, 5-12 Inf (199th LIB), was committed to the operations on 12 May, occupying FSB Brown (YU0737), which had been vacated on 11 May by 5-7 Cav. That night FSB Brown was attacked by a large enemy fore. A ground sweep the following day found 50 enemy dead while US forces suffered one killed and four wounded. At this point the 1st Cav Div had seven maneuver battalions committed to the operation. On 20 May the 1st Brigade air assaulted a battalion in the vicinity of O Rang (YU3663). Contacts throughout the 1st Cav Div AO continued to be light although numerous small weapons and munitions caches were found. During the third week in May, over 600 tons of rice were captured.

b. Division elements reacting to intelligence provided by Cambodian Army officers discovered several more cache sites. As ground elements approached these suspected sites, enemy resistance stiffened. The defenders were identified as elements of the 86th Rear Service Group. Late on the 24th, after several small contacts, ground reconnaissance elements once again reported finds of enemy material. During the next few days the units reported large quantities of enemy material ranging from buttons to complete vehicles in operable condition. The division committed its eighth battalion northwest of Bu Dop on 27 May. On 29 May every battalion committed to Operation Toan Thang 43 reported contact with enemy forces. Enemy cache discoveries had grown in number faster than the committed units could evacuate or destroy their contents.

c. On 31 May the 1st Cav Div was provided another infantry battalion in an effort to increase the ground reconnaissance capability within the AO and on 5 June the Division committed its last remaining organic maneuver battalion to this operation. A large hospital complex complete with an operating room and laboratories was uncovered northwest of Bu Dop at this time. Also, a Navy-developed detection device, Magnetic Anomaly Detector, mounted in a helicopter was employed during this period to locate suspected enemy cache sites in the heavy jungle. At one site located in this manner, tactical air was employed with outstanding results. Subsequent BDA by air cavalry elements revealed a truck park with five 2 ½ ton trucks and several structures. Vehicle machine shop equipment, vehicle spare parts, and large quantities of munitions, as well as medical equipment and supplies, were added to the list of cache discoveries. At one time there were more than 260 tons of rice under US control in the field awaiting evacuation.

d. In the second week of June, elements of the 3rd Brigade uncovered large quantities of communications equipment and repair parts in the vicinity of FSB Gonder, 18 kilometers northwest of Bu Dop. From documents captured in the area, this site is believed to have been COSVN's major signal depot. The third week of June was characterized by increased enemy reaction to the US search activities. The enemy's reaction was highlighted by an early morning ground attack against FSB David in the vicinity of O Rang. Results of this action were 28 enemy killed and the area around the fire base littered with enemy equipment, weapons, and munitions. 29 US personnel were wounded. Throughout the objective area, ground to air fire increased and maneuver units were constantly harried by small groups of enemy. Also, attacks by fire increased in frequency and intensity. Air cavalry and tactical air found lucrative personnel and material targets as the enemy forces attempted to delay or forestall search operations throughout the area.

e. On 20 June the 1st Cav Div started a phased withdrawal from Cambodia. Battalion command posts and artillery fire support bases were repositioned in the RVN near the border. On 27 June the last fire base in Cambodia was closed. During this complex critical withdrawal phase, enemy resistance remained surprisingly light. Full advantage was taken of B-52 strikes to keep the enemy from hindering the US withdrawal as well as to destroy facilities located but not fully searched. The last US ground elements withdrew from Cambodia on 29 June.

a. The 9th Regt, 5th ARVN Division, initiated Cambodian operations on 6 May in conjunction with Operation Toan Thang 45. Two battalions were air assaulted into Base 350 utilizing US air assets. Initial enemy resistance was minimal as ARVN forces were built up in the vicinity of the two landing zones. During the first few days, contacts were light and scattered as the enemy withdrew before aggressive ground reconnaissance forces supported by US tactical air and air cavalry elements. Contacts initially made with cache security forces were followed by sweeps of the contact area which invariably revealed material storage sites. Unlike other storage sites, these caches were normally comprised of weapons, ammunition, and rice. To bolster troop density and security, the 1st ARVN ACR was added to the operation on 11 May.

b. On 21 May, significant enemy resistance to search activities was encountered following which installations and caches were found by all elements. The most important discovery was a bunkered hospital complex with an estimated capacity of 500 patients, captured complete with equipment and supplies. On 26 May, having apparently exhausted major possibilities in the southern portion of the objective area, operations were extended to the north. These expanded search operations met stiff reaction. The enemy made several concerted night ground attacks against ARVN night defensive positions in an effort to prevent or discourage discoveries of additional enemy facilities and supplies. ARVN elements successfully defended their positions while exacting a heavy toll on the attacking enemy forces. During the next two weeks, many light contacts occurred as ARVN forces uncovered more enemy facilities and supplies. The majority of these were medical.

c. In mid-June enemy resistance to ARVN operations stiffened again, and troops in ground reconnaissance were continually harried by small enemy groups. The net effect of these contacts was negligible, but slowed search operations and caused ARVN elements to conduct reconnaissance activities in larger groups. On 20 June, with the initiation of US withdrawal operations, ARVN elements began moving southwest to the vicinity of the RVN border along Highway 13. Enroute units had numerous sharp contacts with enemy forces. Additional base camps and small storage cache sites were uncovered and exploited. By late afternoon on 27 June, all subordinate units had established night defensive positions within RVN. Elements of the 9th ARVN Regiment continued ground reconnaissance in the vicinity of the border until 30 June, at which time the unit returned to its home station near Chon Thanh.

a. Documents captured in late May suggested that Campaign “X” plans entailed the movement of the 5 VC Div toward subregional areas northeast of Saigon, while elements of the 9th VC Div moved into an area northwest of the capitol city in a coordinated attack. The execution of this plan was partially prevented by the capture of a large munitions cache at RANG RANG by the 3rd MSF two months prior to the beginning of the offensive. The coup in Cambodia and allied cross-border operations further disrupted the enemy's plans, and the enemy's divisions withdrew deeper into Cambodia. The major elements of the VC Div left the III MR border area and deployed westward toward the MEKONG River in Cambodia, probably to conduct operations against Cambodian forces in that vicinity. A PW captured on 7 May revealed that the 271st Regiment, 9th VC Division captured CHAK and turned it over to Cambodian Communist forces, while the 272 Regt was located south of the MEKONG in the vicinity of KAMPONG CHAM with an apparent intention of crossing the river. The 95C Regt was identified along Highway 7 and was apparently tasked with an interdiction mission along this LOC. After allied operations in Cambodia began, the major elements of the 7 NVA Div remained generally in the FISHHOOK with the apparent mission of protecting cache sites and attacking allied FSBs in the area. However, identification of the 141 Regt, 7 NVA Div in the immediate vicinity of SNUOL supported the contention that the 141 Regt was the enemy unit that occupied that city during the last week of April. On 7 June, 10 km southwest of SNUOL, a Hoi Chanh identified the 2 Bn, 141 Regt and stated that the mission of the regiment was to protect the SNUOL-MIMOT area. Allied operations into enemy Base Areas 350 and 351 revealed the weakness of the 5 VC Division's elongated area of operation, as contact with the division's regiments during these operations was light. The 5 VC Div had provided security for the 86 Rear Service Group and its base areas in past operations, but seemed primarily concerned with relocating rear service facilities to more secure areas.

b. Enemy forces were apparently surprised by the speed of the allied operations across the border, probably accounting for the fact that reaction to these operations was minimal during the first weeks, and enemy activity throughout the subregions was light in intensity and low in volume. It is significant that the enemy within the corps area did not increase activity in an attempt to relieve pressure on his Cambodian base areas. However, the loss of his supplies and the disruption of his command control along with the increased requirement for enemy operations within Cambodia probably overtaxed his capabilities.

c. Documents captured in June indicated that the 33 Regt had been removed from the operational control of the 5 VC Div and had been resubordinated to the headquarters of MR-7. The division's reorganization included the formation of a new regiment, designated the E6 Regt, and the expansion of the 275 Regt into two regimental sized units. The cadre forming the core of the new regiment was taken from within the 5 VC Div, but the troops probably came several battalion sized infiltration groups just entering the war from the north. The division could have employed another regiment, since the westward shift of the other divisions created such a large area of operation for the 5 VC Division, and allied operations into the area revealed the weakness of its elongated AO. Allied operations into Cambodia also uncovered the existence of three recovery and replacement regiments, the 90, 92, and 94 Recovery and Replacement Regt. The mission of these regiments was to process, equip, and assign newly arrived infiltrators, stragglers and recovered patients to the various enemy units within the corps area and to care for sick and wounded personnel. The cadre strength of these regiments was estimated at 4,550, and the regiments were apparently capable of processing over 14,000 transients and patients at one time. Intelligence gathered in Cambodia also revealed that allied intelligence had greatly underestimated the strengths of COSVN and SVNLA Headquarters. As a result of operations in Cambodia, estimated strengths of COSVN and SVNLA Headquarters were increased from 2,000 to approximately 22,000 persons.

a. Allied operations in Cambodia were primarily directed against the enemy base areas along the northern and western borders of the corps area. The total number of enemy killed was significant; however, since most main force enemy units avoided contact, a large portion of the losses were suffered by rear service elements. The total number of enemy eliminated was 8,836, including 7,807 enemy KIA, 909 PW captured and 120 Hoi Chanh. Enemy logistic losses were more significant: 10,353 individual weapons, 1,786 crew-served weapons, 1,534.8 tons of munitions, and 5,873.6 tons of rice were captured in Cambodia. Some of the caches, such as SHAKEY'S HILL, ROCK ISLAND EAST, and the CITY, were so extensive that they should be considered as enemy logistic depots rather than cache sites. In addition, great quantities of salt, medical supplies and other items such as uniforms, vehicles and communications equipment were uncovered. It is anticipated that the enemy within the III MR, whom these supplies were meant to support, will begin to feel the effects of these logistical losses during the coming months and the effects of these logistical losses during the coming months and there should be a continued decrease in the enemy's offensive activities.

b. Subregion 2 was the most seriously hurt by operations in Cambodia. Toward the end of May, tactical and rear elements of SR-2, SR-3, and SR-6 in SVAY RIENG (P) suffered heavy losses and were fragmented and dispersed by elements of ARVN operation TOAN THANG 42; however, losses suffered by SR-2 elements had the greatest impact in the area of command and control as reports indicated that both headquarters and rear service elements had been widely dispersed and scattered in eastern Cambodia and many key personnel were lost. In the beginning of June, an upsurge of enemy action throughout other areas of South Vietnam marked the initiation of the third phase of Campaign “X”, but the pattern of enemy activity in III MR followed the same low profile noted during May, indicating the enemy's inability to mount a coordinated high point, due to the allies' extensive disruption of his planning and control. The enemy's preoccupation with securing his strategic foothold in Cambodia, however, was also a probable factor in the low level of enemy activity during these months. Captured documents showed evidence of serious enemy morale problems within the corps area, as well as ammunition and food shortages. Documents captured in the PARROT'S BEAK stated that due to numerous difficulties faced by the VC/NVA forces, the subordinate districts of SR-2 would have to supply their own provisions after May 1970. It was also reported that in late March, approximately 30% of the NVA assigned to SR-2 began to agitate openly about returning home. In a report submitted to COSVN in April, SR-2 HQ stated that some 700 men refused to fight, including six battalion commanders and four company commanders. Prior to 19 May, the battalion commander of the 2642 Bn and eight NVA cadre at battalion and company level deserted, stating that they would return to North Vietnam. It is estimated that continuing ARVN operations in the PARROT'S BEAK/ANGEL'S WING area and in SR-2 will further degrade the enemy's morale and offensive capability.

c. The three enemy divisions were less affected by the impact of allied operations in Cambodia. Their rear areas were disrupted and they suffered many casualties, but their command and control, and combat elements generally remained intact. The overall effect in III MR was a reduction in the enemy threat as the 9 VC Div withdrew to the west and the 5 VC Div divided its interest between the northern border area and western Cambodia. At the end of allied operations in Cambodia, of the divisional combat elements, only the 7 NVA Div and two regiments of the 5 VC Div still posed a threat to III MR. The realization that their base areas are no longer safe havens will probably have the most far reaching effect on future enemy logistics organization. The fact that the RVNAF can operate in Cambodia base areas and will probably return will greatly affect the enemy's planning and future methods of operation.

(1) Relief - The area west of the PARROT'S BEAK and south of Route 1 is generally flat, although there are small areas of higher ground scattered throughout. Normal elevations are between 1 and 3 meters with slopes generally less than 1 percent. The northern lowlands are designated as that area generally north of Cambodian National Route 1. Elevations are somewhat higher in this area: 3 to 6 meters. From the DOG'S HEAD in the FISHHOOK the topography is gently to moderately rolling with the local relief varying from 10 to 25 meters and slopes generally averaging three to five percent. The relief does, however, become increasingly more rugged east of the city of SNUOL. This area begins as a relatively smooth, flat plain with an average elevation of 70 meters and increases in elevation to the mountains of the DU MUONG Plateau that give rise to heights of 650 and 700 meters.

(2) Drainage - Throughout the area south and north of Route 1, the drainage is generally poor and large portions of the area are inundated for a large part of the year. With the increase in relief throughout the northern lowlands, the drainage improves considerably. In the FISHHOOK area there are two major streams, the CHHLONG and CHAM. Each of these streams are fed by numerous intermittent and a few perennial tributaries. All other streams radiate from topographic highs and are generally intermittent near their source and become perennial out on the flatland.

(3) Vegetation - The area south of Route 1 is a combination of rice cultivation and swamps with a few patches of brushwoods. Widely scattered palms are sometimes encountered on the dikes of rice fields and small canals. In the northern lowlands, the major vegetation categories are single canopy, light undergrowth forest and rice fields. There are also some small areas of brushwoods and open grassy fields. Starting in the area of the DOG'S HEAD and extending to the DU MUONG Plateau, the vegetation is extremely diverse and of a complicated growth pattern. The predominant vegetation is single canopy, light undergrowth forest; however, there are numerous patches of hulti-canopy, dense undergrowth forest scattered throughout the area. There are large plantation complexes (primarily rubber) and also extensive rice cultivation (vic XT 3593, vic XU 3615 and vic XU 4814). In general, trafficability is directly related to the amount and frequency of precipitation.

(4) Lines of Communication - There are only two roads (Route 1 and 7) that have an all weather classification and two routes (Route 24 and 109) that are partially all weather roads. Routes 13, 78, 131, 254, 701, 1010 and 1011 are limited all weather roads and are motorable throughout the year; therefore, they are considered primary lines of communication. The other designated routes (70, 79, 109, 154, 155, 241, 242, 243, 244, 1012, 1013, 1014, 1091, and 1543) are considered to be fair weather routes; therefore, they are primary lines of communication only during the dry season.

(1) General - During April and May, Southeast Asia is in the transition period between the northeast and the southwest monsoons. The southwest monsoon begins by the end of May. During this time period the low level winds shift from the east-southeast, swinging around to the southwest, bringing on the warm moist flow of air from the Indian Ocean and the Gulf of Thailand. By the first of June, the southwest monsoon is well established. The arrival of the moist air brings a dramatic increase in cloud cover, thunderstorms, and amount of rain, and a decrease in average temperatures. Stratus and fog frequently occur in the mountain valleys during the early morning hours.

(2) Cloudiness, Visibility, and Precipitation - During May 1970, the weather conditions were generally better than is usually expected in Southeast Asia. A light southeasterly to southerly flow persisted throughout the area until mid-month. After 22 May, the flow gradually shifted to a more southwesterly direction and conditions began to be more representative of those normally expected. By the end of the month, low level cloudiness, rain shower, and thunderstorm activity began to increase in frequency, with cloud bases at 1500-2500 ft in the morning and 2500 ft or higher in the afternoon. Surface visibility was unrestricted in most areas, with the exception of patchy fog in the mountain valleys and swampy areas that restricted visibilities to 3-5 miles between 0500 - 0900 hours. Precipitation ranged from 3.25 inches at TAN SON NHUT to 12.64 inches at SONG BE with most areas along the border and in Cambodia receiving 6-8inches. QUAN LOI received a record 5.10 inches of rain during a single thunderstorm. The southwest monsoon officially began on the 28th of May, eleven days after the average starting date. During the first half of June 1970, better than normal conditions continued to exist. In northern III MR and Cambodian border areas, patch stratus reduced ceilings to 500-1000 ft with visibilities 1 - 3 miles in ground fog and haze during the hours from 0400 - 1000. Elsewhere over III MR, morning cloud bases were at 6000+ ft with unlimited visibilities. Afternoon and evening cloud bases in all areas were 2500 - 3000 ft with isolated to scattered rain showers and thunderstorms. Outside of precipitation areas, visibility was unlimited. During the last half of June, ceilings and visibilities followed the same general diurnal pattern as during the first half of the month, cloud bases were from 300-500 ft lower and rain shower and thunderstorm activity increased. Rainfall varied from 6.35 inches at TAN AN to 19.62 inches at QUAN LOI. Most Cambodian border areas received 12-18 inches of rain, with the largest portion occurring during the last half of the month.

7. (U) PSYOP Intelligence: The enemy in the Cambodian border area presented a harder psychological target than is normally encountered in the III MR. The target was composed primarily of hard core NVA/VC units, including COSVN HQ and the 5, 7 and 9 Div. Therefore, the usual Chieu Hoi propaganda appeals based on family ties and hardships were not as effective as they had been with guerrilla type units. The North Vietnamese proved particularly reluctant to accept the standard Chieu Hoi message. It was recognized at a very early stage that quick-reaction was the key to the successful PSYOP exploitation of hard-core targets. The enemy had assured his troops that the political situation in the United States would not permit US forces to operate in Cambodia. Thus President Nixon's decision to send US forces into Cambodia provided a means for attacking the credibility of the enemy's internal propaganda. The psychological impact of the decision was exploited by attacking other internal enemy propaganda themes using the same general phraseology of COSVN Resolutions 9 and 14.

1. (C) There were a total of 216 US killed in action during the month of May 1970; of these, 189 were killed in Cambodia. This monthly total of 216 KIA was the highest since June 1969 (308) KIA) and almost twice the monthly average for the first four months of 1970 (116 KIA). During June 1970, there were 132 US KIA, 95 of which occurred in Cambodia. This was a decrease of almost 50% from May. June's total was only slightly higher than the 116 KIA average for the first four months of 1970.

1. (U) GENERAL: It was apparent during the initial planning for the operation that the supply system required a reorientation to meet the demands of an offensive operation. The requirements for extensive moves by both road and air, and a more demanding rate of resupply and retrograde required rapid readjustment in procedures and movement of cargo. Problems involved in reorienting the systems to offensive combat were rapidly overcome, adjustments were made and in the main, no serious deficiencies existed in supply or services operations.

a. Logistical support agencies responded immediately to the requirements submitted by tactical units. Shortages of supplies, equipment and repair parts were identified, requested and issued, either against valid requisitions or on temporary loans to units. The immediate requirements were for cargo nets and slings, communications and associated electronic equipment, replacement combat vehicles, fire support base kits and combat support vehicles, particularly recovery and bridging equipment. The support rendered by USARV G-4, Saigon Support Command and the Long Binh Depot was outstanding in the expeditious issue against requests.

b. A special effort was made to augment maintenance personnel and repair parts in tactical units in preparation for overland moves to across the border locations. Special contact teams with equipment and repair parts were made available by the 29th General Support Group and moved by road and rotary wing aircraft to the necessary locations. The response by the 29th General Support Group was rapid and in a minimum of 12 hours after notification, all teams had been deployed.

a. The demand for fixed wing Air Force aircraft (C7A, C123, C130) far exceeded that which the system normally requires for day to day resupply and movement of troops. This, coupled with the fact that the 834th Air Division was not provided sufficient notice of the operational planning, initially created a demand that exceeded the capability. This was overcome by rescheduling efforts, additional aircraft being made available, and by improved management of resources by the requesting units.

c. The retrograde of CEM was accomplished by the use of all available means of ground transportation and rotary wing aircraft from the cache sites to forward collecting points established at forward support bases. From these bases, CEM was airlifted by fixed wing and ground transportation to Tay Ninh, Quan Loi and to other designated collected points as established by HQ, USARV. Airlift evacuation was accomplished by special mission airlift requests (SMAR), opportune flights and by units through use of their dedicated C7A airlift capabilities and rotary wing aircraft.

1. II FFORCEV Artillery supported Operation Toan Thang 42 with six batteries of medium and heavy artillery, initially deployed to the north and east of the area of operations to provide maximum support for the maneuver units. Liaison was established with all ARVN Task Forces, III Corps, and IV Corps to further insure timely support. All US Artillery fires in Toan Thang 42 were coordinated and controlled by a forward element of the 23rd Artillery Group, which was collocated with the ARVN III Corps TOC at Go Dau Ha and later at Tay Ninh. During later phases of this operation, two medium and two heavy batteries displaced into Cambodia to keep pace with the rapidly moving ARVN forces. These batteries provided close and continuous support to the maneuver elements, but were not allowed to displace west of Svay Rieng. As the operation progressed, two of the task force continued to operate north of the Dog's Head, while the remaining task force continued to operate in the Parrot's Beak. Each of these operations was supported by a medium and heavy battery.

2. In Operation Toan Thang 43, II FFORCEV Artillery units were initially positioned to support the airlifted elements of the 3rd ARVN Airborne Brigade occupying blocking positions across the border, as well as the 11th ACR and other units attacking overland. Three batteries of medium artillery and six platoons of heavy artillery were deployed forward, utilizing fixed and rotary wing aircraft and road convoy, to seven firing positions in remote areas to the south and east of the Fishhook. Position areas were selected to provide maximum fire support to the maneuver elements upon initiation of the attack. Over 5,500 rounds were fired by II FFORCEV Artillery units in support of Task Force Shoemaker during the first week of operation. Fires of all available artillery were massed on known and suspected enemy locations, paving the way for exploitation by maneuver forces.

3. Aggressive use of artillery early in Operations Toan Thang 4 2 and 43 placed both medium and heavy elements well forward and centrally positioned to support the commitment of additional maneuver units when operations were expanded into Base Areas 350, 351, 354 and 707 in support of the Toan Thang operations except for a few batteries located in other critical areas of III MR, virtually all units of II FFORCEV Artillery were moved o the Cambodian Border, or across it. Heavy artillery platoons were consolidated for employment as batteries wherever possible. During one three-day period, a total of 32 artillery moves were conducted to place the firing elements in the best positions in support of operations in Cambodia. A total of 198 moves were made in response to the needs of maneuver commanders.

1. (U) General. With the initiation of combat operations in Cambodia, engineer requirements in the northern portion of the Military Region were planned to accommodate the movement of US and GVN ground forces with attention focused on overland resupply routes and airfield improvement. Sizeable construction projects and route maintenance requirements were envisioned and necessary steps were taken to provide the required engineer units and heavy equipment to accomplish the tasks.

a. The 31st Engineer Battalion (combat) (Army), reinforced by a light equipment company, established a forward CP at Quan Loi to support operations in the eastern portion of the cross border AO. Primary efforts consisted of opening QL-13 from Loc Ninh into Cambodia to Snuol. Additionally, a 45 foot dry gap span was installed on QL-13 and bomb craters along the route filled. This route was opened to wheel and tracked vehicles within 48 hours of receiving this mission. Another priority mission was to open approximately 22 kilometers of trail from QL-13 into a large cache site known as “The City”. This project was accomplished within 48 hours and assisted in the successful evacuation of large tonnages of captured enemy materiel. Extensive repair to Loc Ninh airfield was required due to heavy traffic. Two taxiways to the existing ramp were constructed to include the installation of a “Hook-out” resupply pad. In addition to repair of existing taxiways, a 500 foot by 250 foot ramp was constructed.

b. The 588th Engineer Battalion (combat) (Army) established a forward CP at Katum to support the western portion of the border AO. Their primary task was the extensive maintenance required to the Katum airfield. Working at night, the unit installed over 600 feet of MBA1 matting at each end of the runway. Additionally, the 588th maintained LTL-4 from Prek Klok to Katum, constructed an all weather back haul road from Katum north to Route 7 in Cambodia and constructed logistical facilities at Katum.

c. To support the 25th Inf Div operations, the 92nd Engineer Battalion (Construction) established a forward CP as Tay Ninh and conducted operations with two organic companies and one platoon from the 362nd Light Equipment Company. This battalion opened and upgraded QL-22 from Tay Ninh to the Cambodian border, completed the upgrade of the Thien Ngon airfield, constructed resupply pads for helicopter operations and constructed by-pass roads to the west and east of the airfield. Overall, the following projects were accomplished during the Cambodian campaign:

3. (C) Land Clearing. Two companies of the 62nd Land Clearing Battalion were deployed into the Fishhook area to support combat operations. A platoon of Rome Plows from the 984th LCC was provided to support engineer operations in opening QL-22 north from Thien Ngon. Rome Plows also supported elements of the 31st Engineer Battalion in opening QL-14A from Bu Dop north to various cache sites in Cambodia. During the period of combat operations, the 60th LCC and 984th LCC cleared a total of 1694 acres. Of particular significance is the role the Rome Plow played in uncovering large quantities of enemy supplies.

1. (U) General. The 12th Aviation Group (Combat) provided direct and general support to II FFORCEV and III MR units participating in the Cambodian Campaign. The support to ARVN III Corps was coordinated by the 12th Aviation Group, using a provisional Arm Aviation Element (AAE) located with III Corps Forward Cp and Go Dau Ha and later at Tay Ninh. The AAE at II FFORCEV Tactical Operations Center coordinated support provided to US units.

a. The 334th Aviation Company (Attack Helicopter) was tasked to provide four Light Fire Teams (LFT) for aerial fire support to ARVN units in contact, escort of US medical evacuation aircraft, escort of VNAF helicopters on combat assaults and escort of US CH-47 resupply aircraft. The basic aviation support allocation consisted of seven command and control helicopters provided daily to the task force commanders and III MR staff. CH-47 helicopters were provided only for emergency resupply and evacuation as required.

b. To assist in positive identification of friendly units during aerial fire missions, the CO 12th Aviation Group established Aerial Aviation Control Teams (AACT). These teams consisted of one UH-1D/H command and control helicopter flown by US personnel carrying a US advisor and an ARVN representative. Through continuous communication with the maneuver forces on the ground and with the III Corps Forward CP, this team provided the necessary control to permit reliable and responsive aerial fire support.

d. Two companies of the 11th Aviation Battalion, the 205th ASHC and the 213th ASHC, were tasked to support the ARVN Airborne Division in closing out three fire support bases in the Fishhook during the final stages of the campaign. To insure close coordination, liaison teams from the 11th Aviation Battalion and 12th CAG were stationed with the headquarters of the Airborne Division at Tay Ninh. The 334th Aviation Company supported the three ARVN combined arms task forces in Phase I of Toan Thang 42, accounting for 365 enemy killed.

e. The forward AAE collocated with III Corps Forward consisted of three officers and three enlisted personnel. This element was situated with G3 Advisor section in the TOC and provided 24-hour support to CG, III MR. This team provided advice to the Deputy Senior Advisor, III MR on Army Aviation matters and coordinated employment of light fire teams and CH-47 recovery missions inside Cambodia. As a secondary mission, the team controlled all US Army aircraft crossing into Cambodia in support of Toan Thang 42. Authority to commit LFT, CH-47, or aircraft recovery missions across the border was at the discretion of the CG, II FFORCEV, while the authority to commit US command control aircraft into Cambodia was reserved to DSA, III MR.

a. The 210th Aviation Battalion, employing fixed wing and rotary wing aircraft, supported Cambodian operations with visual reconnaissance, adjustment of artillery fire, command and staff transportation, radio relay and light cargo transport. In a five day period, five U-1A (Otter) aircraft of the 54th Utility Airplane Company, 210th Aviation Battalion, transported 976 Cambodian refugees and 25 tons of personal belongings from Han Quan in the vicinity of An Loc, RN to a refugee processing point established at Mimot, Cambodia.

b. The 222nd Aviation Battalion employing three assault helicopter companies provided aircraft lift support for liaison, resupply, medical evacuation, command and control, visual reconnaissance, cache evacuation and combat assaults. Additionally, the 273rd Aviation Company (Heavy Helicopter) provided heavy lift assistance to the 1st Cavalry Division. This support consisted of transporting light engineer equipment, artillery weapons and vehicles.

d. During the period 6-13 May, the 3rd Squadron, 17th Cavalry, with two air cavalry troops, was placed under the operational control of the 1st Brigade, 25th Infantry Division to conduct screening missions in Cambodia. One of these troops was placed in support of III MR forces operating in the vicinity of the Angel's Wing. When the 25th Infantry Division returned to RVN on 14 May, the squadron was placed OPCON to the division and tasked to continue air cavalry operations in Base Areas 354 and 707. This mission continued until 22 June when the squadron was given an additional AO which encompassed Base Areas 352 and 353 and extended into Cambodia to the 30 kilometer limit. Primarily, the squadron conducted screening operations while remaining immediately responsive to mission requests by the 11th ACR operating in the Fishhook. On 27 June, the squadron assumed OPCON of the 11th ACR's air cavalry troop and began an intensive low level reconnaissance operation in the Fishhook area in support of a comprehensive interdiction campaign directed by the 25th Infantry Division. These operations were conducted in conjunction with a massive destruction program employing tactical air, B-52 strikes, artillery fires and air cavalry to inflict maximum damage to remaining unexploited cache sites and base areas.

a. Tactical air support of the Cambodian Operations was provided by the 3rd, 12th, 31st and 55th Tactical Fighter Wings. These wings flew a total of 6,017 FAC directed sorties and 175 radar directed sorties in support of the Cambodian operations. The results of these air strikes included 520 enemy confirmed killed, 270 estimated killed, 507 secondary explosions observed, and destruction of 4,571 fortifications, 52 vehicles, 30 bridges and an estimated 268 tons of rice.

d. Tactical airpower was used initially to assist ground forces in their penetrations into Cambodia and to destroy known enemy base camps and cache sites. Subsequent strikes neutralized helicopter landing zones and destroyed other enemy field fortifications protecting adjacent base camps and cache sites. The jet fighter-bombers together with the night gunships and flare ships assisted in dominating the battlefield and in isolating it to deter enemy evacuation of caches. Generally good weather allowed the employment of an average of 98 sorties daily and permitted gunship cover throughout the night.

a. A total of 186 B-52 Bomber strikes supported operations in Cambodia during the period 24 April through 30 June 1970. Initial strikes in Cambodia were targeted against suspected base camps, transshipment points and staging areas and were designed to assist penetration of the border areas and facilitate rapid advancement to initial objectives. A total of 36 strikes were employed in this role in the Fishhook area and Base Areas 350, 351, and 353.

b. As consolidation of the initial objectives occurred, targeting emphasis was shifted to support operations designed to destroy enemy troop concentrations, disrupt command control facilities, and destroy rice and munitions caches which could not be fully exploited. The most significant BDA reported was 151 confirmed KBA from a series of six strikes on 11 May west of Mimont. This exploitation phase of the operation was supported with a total of 89 strikes.

c. Withdrawal operations were supported by 36 strikes concentrated in the Fishhook and north of Base Area 351. The objective of these strikes was to assist in the extraction of US and ARVN units by interdicting known and suspected enemy troop concentrations. Midway through the withdrawal phase, troop extraction had successfully progressed to the extent that Arc Light emphasis was shifted to known and suspected arms and rice caches.

4. (C) COMMAND AND CONTROL: The CTU controlled the operation from Ben Keo Naval Base (XT2345) on the Co Dong River. A forward CP was maintained inside the RVN border on an armored command and control boat. US advisors maintained their area communication nets and were responsible for control and employment of US air and artillery support. USN Seawolf gunships from Ben Luc were temporarily based at Tay Ninh West to provide gunship support to Riverine Operations.

1. (U) General. GVN military forces contributed significantly to the overall success of the Cambodian campaign. III Corps forces along with the ARVN Airborne Division and the 9th Regiment of the 5th ARVN Division demonstrated their ability to carry on the war against the communist insurgent independently of US direct advice or support. While there were weaknesses noted in some areas, there was also favorable progress realized in the application of sound tactical direction and the conduct of the land battle.

b. ARVN ground commanders developed an over reliance on US gunship support. Routinely, gunships were requested before the tactical situation had fully developed, often resulting in no identifiable target or employing gunship ordnance against inappropriate targets, e.g., bunkers. Additionally, improper utilization of direct support artillery was a common occurrence. The tactical commander preferred to employ gunships and accept delays in reacting to initial contact rather than use responsive light and medium artillery fires. Increased emphasis and continued coordination by US advisors materially improved the fire coordination standards of these ARVN units, particularly as experience was gained.

c. Medical evacuation of casualties by VNAF helicopters was not responsive to the requirements. Delays in excess of one to two hours could be expected before VNAF helicopters would report on station. Night missions were rarely flown by VNAF pilots due to inexperience and limited training in night flying. III MR had only six H-34 helicopters available for both general support and medical evacuation airlift; consequently, maintenance requirements and other priorities contributed to lengthy delays in responding to emergency situations. US helicopter assistance particularly in Medevac missions at night alleviated some of the strain on Vietnamese helicopter use.

a. The ARVN Airborne Division was deployed in the Fishhook area, generally in dense jungle terrain. Although all battalions displayed aggressiveness initially, the enemy was able to take advantage of the jungle to employ ambushes and harassing tactics to cause delay and inflict casualties on airborne units. Heavy reliance on helicopter gunships created unnecessary delays in exploiting enemy contacts. The failure to employ artillery initially in contacts often resulted in additional friendly casualties, with the enemy withdrawing before gunship support arrived.

c. Other noticeable weaknesses in airborne unit operations were reluctance to aggressively exploit and evacuate cache sites. Upon discovery of a cache, units did not conduct comprehensive searches for other cache sites in the general area and failed to outpost cache discoveries adequately to prevent enemy harassment. In this regard, combat patrols and stay behind ambushes were no used a frequently or aggressively as needed.

a. The 9th Regiment was deployed in Base Area 350 in terrain characterized by rolling hills and single canopy vegetation. Ground operations were generally limited to company and battalion size reconnaissance-in-force operations with little tactical direction from the regiment. Battalion commanders were assigned areas of operations and deployed their forces independently within these areas. Generally, the efforts of the battalions were not coordinated by regiment to insure a coordinated, controlled search.

b. Gunships were usually the first type of fire support requested when contacts were made with enemy forces. While units showed proficiency in the use of ARA, often the tactical situation was best served by immediate employment of direct support artillery. There was also a reluctance to use close air support. Except for the initial air assaults into Cambodia, pre-planned air strikes were not used. Immediate air strikes were used only when a unit became heavily engaged and was still far enough from the enemy to permit its use without suffering friendly casualties.

c. As cache sites were found, units focused attention on evacuating the contents of the cache rather than searching for other caches. Consequently, search efforts were less than complete. Moreover, security became lax when ARVN units discovered supply caches. On several occasions, the enemy was permitted to get within small arms and B-40 range of the interior of the battalion because of lack of adequate outposts and ambush patrols.

5. (C) Summary. ARVN initiated and controlled operations during the Cambodian campaign have had a severe impact on the enemy. The successes of Vietnamese units in locating and evacuating captured material and destroying base camp complexes had a profound effect on both sides. The enemy lost a significant number of personnel, to include destruction of several units, and large quantities of supplies and equipment. For the III MR, the campaign was a series of missions which, in spite of the shortcomings noted above, earned it high marks and imbued it with confidence and esprit.

1. (U) General. The influence of the Cambodian operations on the majority of CORDS area of interest was primarily an intensification of pacification and development activities within III MR. More directly, there were operations conducted in the Angel's Wing area by RF/PF units from Tay Ninh. These operations were distinct contributions to the success of the cross border operations. Significant effects also encountered were the large number of refugees generated by military operations within Cambodia.

a. Territorial Forces. The most noteworthy RF/PF operations were conducted by territorial forces from Tay Ninh Province. Seven RF companies, commanded by two inter-company group headquarters, and the 58th RF Battalion were augmented by various RF platoons and the Provincial Reconnaissance Platoon. These forces were given their own areas of operation and were responsible to the subsector commander. Their mission was to locate enemy units and caches that had not been uncovered by the fast moving armor land mechanized regular force sweeps in and around the Angel's Wing. During this period the RF/PF conducted a total of five operations in Cambodia resulting in ten days of actual combat. The terrain in which they operated was characterized by rice fields, tree lines and wooded area. Most of the uncultivated areas were occupied by enemy forces in well fortified positions. Initially, engagements with the enemy revealed them to be confused, disorganized, and obviously without adequate command and control. Where resistance was offered, it was generally token in nature, resulting in 150 enemy captured and 64 killed. By late May, resistance during contacts stiffened as the enemy was able to reestablish command and control. Despite this increased resistance, the enemy RF/PF loss ratio was over 30:1.

b. Refugees. 36,000 refugees from Cambodia sought refuge in III MR, either directly or indirectly due to the Cambodian operations. The refugees were received, processed and cared for by the Vietnamese Government in an outstanding manner. 922 tons of captured rice were backhauled from enemy caches and distributed to refugees in III and IV MRs. The Refugee relief operation was a positive example of successful Vietnamization. No major problem area was encountered.