General Hieu was assigned Commander of 5th Infantry Division on 8/14/1969 and left this position on 6/9/1971.
General Hieu's first efforts were to strengthen the combat capability of the 5th Division. To achieve this goal, according to Colonel John Hayes, Senior Advisor of ARVN 5th Division, General Hieu made use to the fullest the attack role of the 1st Armored Regiment and gave orders to units of the division to switch from defensive to attack posture. By initiating a program of carrying the war to the enemy, in a year, the 5th Division bulldozed VC strongholds located in Binh Duong, Binh Long and Phuoc Long Provinces (Combat Zones D, C, Ho Bo, Iron Triangle...) forcing the VC to move its Southern Central Command headquarters to neighbor Cambodia.
Colonel Nguyen Khuyen, Director of III Corps Military Security Bureau, noted:
This showed that units of the 5th Division had executed strictly the order issued by its commander in the meeting of 10/07/1970, and had achieved results:
When General Hieu took over the command of the 5th Division in 8/1969, its three 7th, 8th, and 9th Regiments were holding a secondary role as units attached to the US 1st Infantry Division in combined Dong Tien Operations. Merely two weeks following General Hieu's arrival, General McAuliffe, Assistant Commander of US 1st Infantry Division, paid a visit to General Hieu to discuss the Dong Tien operations on 09/01/1969. He was impressed by General Hieu's extensive knowledge and vast experience in joint operations, as well as his clear cut stance and self-assured confidence. And one week later, on 09/06/1969, in a meeting between the two commands of ARVN 5th Infantry Division and US 1st Infantry Division, it was the US 1st Infantry Division Commander General Milloy's turn to be impressed by General Hieu's aura: despite his status of a newcomer, General Hieu demonstrated that he was in control of the military situation and dictated the modalities to be adopted in joint operations of the two divisions. This fact was comprehensible since General Hieu came to the 5th Division with a baggage full of experiences acquired through numerous joint operations with American and Korean units during his three years at the command of the 22nd Division.
Besides conducting Dong Tien joint operations with the US 1st Infantry Division, General Hieu busied himself with moving his divisional headquarters to Lai Khe relinquished by the US 1st Infantry Division. He performed this operation swiftly and was able to move his headquarters in on 02/ 27/1970, three weeks ahead of time. Furthermore, the taking-over of this American base camp was done without the scandal of equipment and material embezzlement which occurred in the case of Dong Tam base camp in IV Corps and Duc Co, Dakto, Le Thanh, Play Mo Rong, An Khe base camps, etc... in II Corps.
The headquarters of the US 1st Infantry Division was moved from Lai Khe to Di An. And by the end of April 1970, the last units of this division boarded the ship to leave Vietnam and return to the United States as planned by the program of Vietnamization of the war. General Hieu's opinion, when asked by General Tran Van Don, regarding this program was that it weakened the ARVN because it did not allow additional troops to replenish the void left by the withdrawal of American troops. Although General Hieu complained his 5th Division had to assume the responsibility of other territories left by two American divisions, in fact, he showed his outstanding military skills in utilizing to the maximum the limited forces in hand and in succeeding to force the VC out of the three provinces of Binh Duong, Binh Long and Phuoc Long in short period of time. This feat allowed him to entrust the Rifle Forces and the Popular Forces with the security task and to afford to send his main forces across the Cambodian border in pursuit of the enemy.
April 1970 was also when the 5th Division joined with units of III Corps, IV Corps, and American units in cross-border operations as ordered by President Nixon. In Operation Toan Thang 46, from May to July 1970, the 9th Regiment of 5th Division joined the US 11th Armored Cavalry Regiment to attack the enemy in the Fish Hook area north of Loc Ninh.
In parallel with joint cross-border operations with American and Vietnamese forces (Toan Thang 42, 43, 44, 45 and 46), the 5th Division also unilaterally conducted cross-border operations at regimental level named Toan Thang 1/B/5, 2/B/5, 3/B/5, 4/B/5, 5/B/5 and 6/B/5 with air support provided by the US 317th Air Cavalry.
By the end of June 1970, American troops were forbidden to cross the Cambodian borders, and cross-border operations were solely conducted by Vietnamese units. Within the III Corps operational areas, General Do Cao Tri consulted with General Hieu then entrusted General Hieu the design and the implementation of a luring tactic that would involve all three divisions of III Corps (the 5th, the 18th, and the 25th). General Hieu's concept was to establish a trap at Snoul city with the 8th/5th Division as bait and to have eight task forces composed of units of the 18th and the 25th Divisions conducting operations in the nearby areas of Chup Plantation as diversionary activities; these eight task forces comprising from 18 to 20 thousands troops would serve as reserved forces which would corner the enemies when they fall into the trap.
At the end of October 1970, General Hieu launched Operation Toan Thang 8/B/5 composed of three task forces, in a cross-border recon assault into the Snoul areas to insert recon units and to implant sensors around Snoul for intelligence gatherings as the preparation phase in the luring tactic.
As the luring campaign was unfolding quietly, in February 1971, President Thieu intended to dispatch General Tri to I Corps to replace General Hoang Xuan Lam to salvage the Lam Son 719 Operation. General Tri wanted General Hieu to replace him as III Corps Commander. As things were still up in the air, General Tri was killed in a helicopter accident on 2/27/1971. But then instead of choosing General Hieu, President Thieu appointed General Nguyen Van Minh to the position of III Corps Commander. General Hieu sensed immediately that his large-scale luring plan was no more 100 percent backed by the leadership at the corps level.
At the beginning of May 1971, General Hieu advised the 8th Task Force Commander "to frequently remind units to take proper action in defending bases and camps, to dig defensive and combat fox holes in order to resist and sustain enemy attack until the arrival of reinforcement units." and in order to reassure the 8th Task Force, General Hieu reiterated that the reserved forces were standing ready nearby: "our two reserved main forces for this operation - 18th and 25th Divisions - are on the ready position, lurking not far away in the area southeast of Chup Plantation."
But then when the enemy started to mince the bait with waves of attacks at a regimental level against 8th Task Force units in Snoul at the end of May, General Minh denied General Hieu the use of the reserve force composed of eight task forces to corner the enemy as planned. And General Hieu was forced to retreat the 8th Task Force to Loc Ninh. Although the withdrawal was considered as a success, General Minh used the heavy loss suffered by the 8th Task Force during the retreat as a pretext to relieve General Hieu of his command and replaced him with a member of his Delta Gang.
Objectively, it must be recognized that III Corps under General Do Cao Tri's leadership and the 5th Division under General Hieu's leadership, during the years 1969-1971, proved that the ARVN had ascertained a level of maturity that allowed its troops to replace the American ground forces efficiently. The Viet Cong were denied safe-havens within the III Military Region, and III Corps was able to operate at will across the Cambodian borders. President Thieu committed a big mistake in allowing the introduction of General Nguyen Van Minh's Delta Clan to take over the III Corps, for by doing so, he started the process of deterioration of the III Corps in particular and of the entire ARVN in general.
Nguyen Van Tin